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TCrate
09-24-2007, 09:53 PM
Has anyone out there done any mods to their Ford 351. I recently replaced the GT 40 heads, put an RPM performer intake and went from a 4010 Carb to a 4160. I have really had to go up in Jet size to get the air fuel mixture right. Wondered if anyone else had done something similar.

BuzzSr
09-24-2007, 09:54 PM
What did you replace the GT-40 heads with?

TCrate
09-24-2007, 10:04 PM
I replaced them with RHS heads. Quite frankly I would not recomend them. The rest of the story is I got 30 hours out of them. The intake valve on # 3 cylinder was not seating. One week before vacation, I had to pull the heads, get them reground, new valve guides and put everything back together. The machine shop said the guides were sloppy. You could see on the seats where the valves were not seating right. Fat seat wear on one side and skinny seat pattern on the other. These were assembled from the factory. I did add roller rockers but I did not change the cam.

EricB
09-24-2007, 10:22 PM
What did you do with your GT40 heads?

drbesvold1
09-24-2007, 10:26 PM
Has anyone out there done any mods to their Ford 351. I recently replaced the GT 40 heads, put an RPM performer intake and went from a 4010 Carb to a 4160. I have really had to go up in Jet size to get the air fuel mixture right. Wondered if anyone else had done something similar.
i replaced my cam shaft and distributor and bought a new 4160 and i am still having trouble with the mixture im just going to take my boat into the shop and let them work on it and figure out the problem

BuzzSr
09-24-2007, 10:28 PM
Just wondering as the the GT-40 heads are not that bad. If you really want a difference you need to change the cam. Much cheaper than new heads and more bang for the buck. I am planning this improvement soon. Ford does make a GT-40P head that is a slight improvement over the standard GT-40. There again, a new cam will give you a bigger improvement.

Just curious, are the RHS heads aluminum?

Prostar Rich
09-25-2007, 06:36 AM
It would be interesting to know the flow numbers between the various sets of heads that are available. It may be possible to get very good flow numbers by having the stock heads pocket ported. Add in a set of roller rockers and a nice cam and you would end up with a nice top end engine package. On a boat, port velocity would be key. Cam selection would also play a major role. One of the most common mistakes in hot rodding is picking to large of a cam.

Prostar Rich

TRBenj
09-25-2007, 09:32 AM
Ive done a little bit of work on the top end.

http://i41.photobucket.com/albums/e260/TRBenj/GL07motor.jpg

It doesnt include the RHS heads, but here is a Head Flow Chart (http://www.allfordmustangs.com/Detailed/630.shtml) for small block Fords.

Everything Ive read indicates that it is not worthwhile to port the stock (non-HO E7) heads. It would take a professional to get them to flow equal to the GT40's, and by that time, youve outspent what the GT40's would cost. Not to mention the GT40p's are even better and have smaller combustion chambers, which boost the CR ~1 point (not to mention cheaper).

DooSPX
09-25-2007, 10:47 AM
:headbang: :love:

every time i see that engine...

im waiting for something to happen to mine, so i can upgrade... LOL:rolleyes:

Prostar Rich
09-25-2007, 10:48 AM
Ive done a little bit of work on the top end.

http://i41.photobucket.com/albums/e260/TRBenj/GL07motor.jpg

It doesnt include the RHS heads, but here is a Head Flow Chart (http://www.allfordmustangs.com/Detailed/630.shtml) for small block Fords.

Everything Ive read indicates that it is not worthwhile to port the stock (non-HO E7) heads. It would take a professional to get them to flow equal to the GT40's, and by that time, youve outspent what the GT40's would cost. Not to mention the GT40p's are even better and have smaller combustion chambers, which boost the CR ~1 point (not to mention cheaper).

Excellent information and right on the money. The smaller combustion chambers will have good port velocity and the boost in CR is an added bonus.

You have done your homework and you have one hell of an engine there. The exhaust work is a work of art in it self. Great job. Did you swap the cam as well?

Thanks for posting the info and the pic.

Prostar Rich

TRBenj
09-25-2007, 11:12 AM
Thanks guys.

Did you swap the cam as well?
I did. The new cam went in at the same time as the heads and intake. Ignition was done beforehand and the exhaust and RR's were added later. Its best to have the cam matched to the rest of your components (heads, intake, CR). Intended use, RPM range, etc also come into play for good cam selection. I highly recommend Cam Research (http://camresearchcorp.com/), as they only do Fords and they really know their stuff. Theyre also very familiar with the particular needs of ski boats- which is more than I can say for Comp and Crane. Every cam is custom, and their prices are better too.

Just an FYI- everyone says that they want low end torque in a ski boat, but I dont buy it. The only time Im under 2500 RPM is at idle- I get well over 3k coming out of the hole. I built my motor with midrange power in mind and picked up power everywhere, most noticeable was the holeshot through midrange- perfect for skiing. Top end gains are there as well, and are good for barefooting.

TRBenj
09-25-2007, 11:15 AM
I replaced them with RHS heads. Quite frankly I would not recomend them. The rest of the story is I got 30 hours out of them. The intake valve on # 3 cylinder was not seating. One week before vacation, I had to pull the heads, get them reground, new valve guides and put everything back together. The machine shop said the guides were sloppy. You could see on the seats where the valves were not seating right. Fat seat wear on one side and skinny seat pattern on the other. These were assembled from the factory. I did add roller rockers but I did not change the cam.
TCrate, which heads did you go with? Aluminum/Cast iron, runner length, combustion chamber size? Did you pick up power?

Did you set the lifter preload properly when you installed them?

DooSPX
09-25-2007, 05:11 PM
TRBenj, how would your cam (what are the spec's again) and GT40P's and a Performer intake (clearance issues under MC box) and RR's perform with out the fancy exhaust manifolds??
and for the heck of it, can you send a link to where you got the manifolds from?

thanks so much

TRBenj
09-25-2007, 05:52 PM
TRBenj, how would your cam (what are the spec's again) and GT40P's and a Performer intake (clearance issues under MC box) and RR's perform with out the fancy exhaust manifolds??
and for the heck of it, can you send a link to where you got the manifolds from?

thanks so much
For the money, you cant beat a head-intake-cam upgrade on these motors, especially when going with the GT40p's. Ive read good things about the RR's (thats why I added them) but I cant say how much they added since I did the exhaust at the same time. Those 2 things were really icing on the cake, as my boat performed VERY strong last year without them.

From memory, the cam specs are:
Lift (1.6, I/E): .490/.490
duration (I/E): 218/222
lobe seperation (deg): 110
RPM range: 2500-5200

Manifolds were made by Hi-Tek Marine (http://www.hitekmarine.com.au/products.htm) of Australia. I can put you in contact with the US distributor if you want- he puts orders through in bulk to lower costs.

DooSPX
09-25-2007, 07:39 PM
Thanks TRBenj...
when it comes to modding these Ford PCM/Indmar, Your the best I know. your info is so helpful, thank you for sharing your knowledge.
btw, even though I am a MC guy through and through, your CC is very nice.
is that cam a Hydro Flat Tappet?
what do you think the torque would be with the cam/gt40p's/eddy performer and the RR ?? I saw you estimated 320hp before the exhaust, but I would love to know what the torque is as a educated guess?



For the money, you cant beat a head-intake-cam upgrade on these motors, especially when going with the GT40p's. Ive read good things about the RR's (thats why I added them) but I cant say how much they added since I did the exhaust at the same time. Those 2 things were really icing on the cake, as my boat performed VERY strong last year without them.

From memory, the cam specs are:
Lift (1.6, I/E): .490/.490
duration (I/E): 218/222
lobe seperation (deg): 110
RPM range: 2500-5200

Manifolds were made by Hi-Tek Marine (http://www.hitekmarine.com.au/products.htm) of Australia. I can put you in contact with the US distributor if you want- he puts orders through in bulk to lower costs.

TCrate
09-25-2007, 09:50 PM
TR Benj, the heads are cast. I shied away from aluminum because I pick up a lot of weeds in my canal. As for the lifer preload I did set them with the help of an engine builder. He did most of the selection of the parts. He wanted to put a new cam in and I wish I had followed his lead on that one. However, the thing I have noticed is I used to be 1 to 1 in terms of RPM and speed. I am now at a different ratio. When I run 3,000 RPM's I am at 32 MPH. I thought it was the speedos at first But I checked them in the course and with GPS and they were very close.

TCrate
09-25-2007, 09:57 PM
TRBenj,
Another question. When you made these mods how much did you have change the jetting in your carburetor. I have gone from .69 to .78. I think I am going back down to .76 as I am a little on the rich side. Better rich than lean. It would be nice to find a way to install and oxygen sensor into these manifolds to be able to dial them in scientifically. Anyone ever found a way to do this?

TRBenj
09-26-2007, 10:22 AM
is that cam a Hydro Flat Tappet?
what do you think the torque would be with the cam/gt40p's/eddy performer and the RR ?? I saw you estimated 320hp before the exhaust, but I would love to know what the torque is as a educated guess?
There are guys who know more on the CC site- thats where I picked up most of my knowledge. Thanks for the comment.

Yes, my cam is a hydraulic flat tappet. Solid wouldnt make any sense for this application. Roller would be nice, but its $$$ to convert the flat tappet block (hp/dollar is pretty low), so I didnt go that route. Maybe on the next project.

I would speculate that the torque would have to be close to 400 lb ft with those upgrades. I believe Ive read that the PCM Proboss/GT40 (HO 351w) is pushing that figure (380ish?), so with a few more HP due to the cam and slightly better heads Id say 400 is pretty close.

TCrate, Id say youre way way rich on your jetting. I started way rich too. Stock jetting should have been 66/72 (front jets/rear plate) on my 4160. I converted the rear plate to a metering block with jets and installed 72/82. Way rich. I still havent dialed in the jets yet (still gotta plug chop) but I think Im pretty close at 68/74. I recommend converting to the metering block so you can dial in the secondaries. With the plate installed, you'll have to run way rich on the primaries just to keep from running lean at WOT. With 76 or 78 in the front youre fatter than would be required by a big block motor- and we're just not flowing that much air. Drop the jetting back to 69 and start again- you should pick up power (best performance will result from being just on the safe side of too lean).

To do the heads and intake and not the cam, I wouldnt be surprised if you didnt pick up a ton of power. With the increased air flow, you need more fuel to make it all work! A cam would really bring that package topgether. The non-linearity of the speed/RPM is very strange. Although the engine is likely more efficient at any given RPM, the hull and prop are what factor into the slip %. If you changed the prop at the same time, that would account for the difference. Otherwise, something just isnt adding up.

rcnjson
09-26-2007, 12:09 PM
My boat has a stock motor with a few "bolt on's". Its true, I "bolted on" canfield heads, 1.6 roller rockers, and an edlebrock RPM intake. Last spring I also "bolted on" EFI and put a sticker on the windshield (every sticker is worth 5 HP's). My winter project is going to be "bolting on" a new bottom end. My short block has 2300 hours on it and has some serious blow by issues.

In all seriousness, the heads I run are way too big for the stock motor. The boat has pretty low compression to start with and then the bigger combustion chamber lowers it even more. I ran these heads on a pretty hot 347 and that combo worked well but the compression was way higher. To fully utilize these heads I would either need to bump compression or increase cubic inches or both. The low R's really suffer from the stale air but it sure does wake up after 3500. So I might do a stroker, we'll see, haven't decided yet.

TRBenj,
Is the cam duration that you showed the "advertized" duration or was that at .050" tappet lift? Reason I ask is it looks tight, but that may be so as boats are generally used in a lower RPM range and too much duration can hurt the low end. I am still running the stock cam but that will probably go. If the duration listed is at .050", that cam is really close to a B303 from ford and I just so happen to have one of those laying around.
k

TRBenj
09-26-2007, 12:23 PM
TRBenj,
Is the cam duration that you showed the "advertized" duration or was that at .050" tappet lift?
Thats at .050, I believe. I should have Cam Research resend my cam card, as I think I lost it.

When you do the cam, dont forget to change the timing set, especially since you have high hours. If you can get compression up to 9.5-10 (maybe even 10.5), that will really wake the motor up. The B303 cam might be a little small if you go with a stroker, though.

Prostar Rich
09-26-2007, 12:25 PM
[QUOTE=rcnjson]My boat has a stock motor with a few "bolt on's". Its true, I "bolted on" canfield heads, 1.6 roller rockers, and an edlebrock RPM intake. Last spring I also "bolted on" EFI and put a sticker on the windshield (every sticker is worth 5 HP's). My winter project is going to be "bolting on" a new bottom end. My short block has 2300 hours on it and has some serious blow by issues.

In all seriousness, the heads I run are way too big for the stock motor. The boat has pretty low compression to start with and then the bigger combustion chamber lowers it even more. I ran these heads on a pretty hot 347 and that combo worked well but the compression was way higher. To fully utilize these heads I would either need to bump compression or increase cubic inches or both. The low R's really suffer from the stale air but it sure does wake up after 3500. So I might do a stroker, we'll see, haven't decided yet.


The additional cubes of a stroker engine would really help you out. I have first hand experience on a GM LT 1 stroker engine that I installed in a 96 Impala SS. I had that engine stroked to 396 cubes and the torque is quite impressive. I went with a forged bottom end to handle a 200 HP shot of NOS for any Vette that I may encounter that might want to play. Made for a real sleeper and stop light warrior on the street.

In a boat I would think you would find similiar results. My question would be can the trans hold up to the additional power and torque?

Take care,
Prostar Rich

rcnjson
09-26-2007, 12:38 PM
The B303 cam might be a little small if you go with a stroker, though.

Perhaps, but don't forget I have 2.05 intake valves and too much lift/duration and I'll have a tie on my hands. You know a tie where the piston and valve get to the same place at the same time.

Thanks for the info, and I did change the timing set last spring durring the EFI conversion, I forgot to list that in my "bolt on's" My old set had so much slop I couldn't get an accurate timing reading and I figured I needed that to get any sort of starting point for the tune with the EFI.

One thing I over looked is the B303 is a roller cam and if I'm not mistaken the roller cams have a different base circle than the non-rollers and I think that causes a problem with the lifters being too high in the lifter bores and a loss of pressure or something like that. I know there is a roller conversion (as mentioned, spendy) for non-roller blocks, but if I am building it might just be easier to find a roller block. Like I said, we'll see, I haven't really though too hard about it, I just know it is in serious need.

Thanks again!
Jason

Hey Rich,
where do you live?
I'm in the midwest too. Just north of Milwaukee.

woodskier
09-26-2007, 12:54 PM
For the money, you cant beat a head-intake-cam upgrade on these motors, especially when going with the GT40p's. Ive read good things about the RR's (thats why I added them) but I cant say how much they added since I did the exhaust at the same time. Those 2 things were really icing on the cake, as my boat performed VERY strong last year without them.

From memory, the cam specs are:
Lift (1.6, I/E): .490/.490
duration (I/E): 218/222
lobe seperation (deg): 110
RPM range: 2500-5200

Manifolds were made by Hi-Tek Marine (http://www.hitekmarine.com.au/products.htm) of Australia. I can put you in contact with the US distributor if you want- he puts orders through in bulk to lower costs.
Would love some approximate pricing and the US contact for the exhaust manifolds. About to replace a leaking one on my 84 S&S Ford 351, and these look much nicer then the other after market ones I have priced. I checked the web link you posted, but it does not give any info at all.

TRBenj
09-26-2007, 02:32 PM
Perhaps, but don't forget I have 2.05 intake valves and too much lift/duration and I'll have a tie on my hands. You know a tie where the piston and valve get to the same place at the same time.

One thing I over looked is the B303 is a roller cam and if I'm not mistaken the roller cams have a different base circle than the non-rollers and I think that causes a problem with the lifters being too high in the lifter bores and a loss of pressure or something like that. I know there is a roller conversion (as mentioned, spendy) for non-roller blocks, but if I am building it might just be easier to find a roller block. Like I said, we'll see, I haven't really though too hard about it, I just know it is in serious need.
Woodskier, I sent you a PM.

To figure out how much cam you can run, Id be on the phone with the head manufacturer. Heads that big were meant to be used with big cams, so I doubt youd have a problem. A friend of mine just built a 408w with 2.02/1.60 valves and a .513/.513 (212/218 dur) cam- which he admitted was pretty conservative. A .490/.490 would be pretty small on a stroker.

Concerning roller, it is $$$ to convert- either by machining the block for the spider retainer or going with the $400+ tie-bar lifters. You simply cant use a roller cam in a flat-tappet block. The base circle may be different, and the lobe material is different for certain- so I wouldnt even entertain the idea of using the flat tappet lifters with a roller cam. For less than $200 for a cam/lifter set, you might as well get a custom grind FT from Cam Research.

rcnjson
09-26-2007, 03:07 PM
Heads that big were meant to be used with big cams

Good point. The head manufactures usually take the cop out of "well every combo is different" when you start talking about piston to valve clearance. The only way to be sure is to check it yourself with plasti-gage. I usually look for about .100" to be on the safe side. It is a real pain if it doesn't check out though. All parts have been purchased, assembled and balanced at that point so doing it over gets expensive (I might know from experience).
Jason

TCrate
09-26-2007, 10:23 PM
[QUOTE=TRBenj]

TCrate, Id say youre way way rich on your jetting. I started way rich too. Stock jetting should have been 66/72 (front jets/rear plate) on my 4160. I converted the rear plate to a metering block with jets and installed 72/82. Way rich. I still havent dialed in the jets yet (still gotta plug chop) but I think Im pretty close at 68/74. I recommend converting to the metering block so you can dial in the secondaries. With the plate installed, you'll have to run way rich on the primaries just to keep from running lean at WOT. With 76 or 78 in the front youre fatter than would be required by a big block motor- and we're just not flowing that much air. Drop the jetting back to 69 and start again- you should pick up power (best performance will result from being just on the safe side of too lean).

TrBenj,
You seem to have a good grasp of jetting. Being somewhat of a rookie at jetting do you have any suggestions on where I can learn the right way to jet this engine. I have been doing runs at 2800, shutting the motor off and then checking plugs. They keep showing lean. I think I am not seeing the plug far enough down in the plug to read it right. I am assuming that you have to read the ceramic at or below the burn point for the RPM range you are running at. Does that make sense. In other words you can read idle at the tip of the ceramic. But as you go up in RPM you have to go down on the Ceramic. I have also read you should not read the ceramic but the ring at the end of the threads. I think this is only for WOT. Any suggestions. Thanks.


TC

Laurel_Lake_Skier
09-26-2007, 10:42 PM
It is a real pain if it doesn't check out though. All parts have been purchased, assembled and balanced at that point so doing it over gets expensive (I might know from experience).
Jason

Not as expensive as finding out about the problem after you fire the engine up.8p

Prostar Rich
09-27-2007, 08:03 AM
Thanks again!
Jason

Hey Rich,
where do you live?
I'm in the midwest too. Just north of Milwaukee.[/QUOTE]


Jason,

I live in the NW burbs of Chicago. I have a second home on Lauderdale Lakes, WI where I use my MC.

Prostar Rich

TRBenj
09-27-2007, 09:46 AM
TrBenj,
You seem to have a good grasp of jetting. Being somewhat of a rookie at jetting do you have any suggestions on where I can learn the right way to jet this engine. I have been doing runs at 2800, shutting the motor off and then checking plugs. They keep showing lean. I think I am not seeing the plug far enough down in the plug to read it right. I am assuming that you have to read the ceramic at or below the burn point for the RPM range you are running at. Does that make sense. In other words you can read idle at the tip of the ceramic. But as you go up in RPM you have to go down on the Ceramic. I have also read you should not read the ceramic but the ring at the end of the threads. I think this is only for WOT. Any suggestions. Thanks.
I dont think youre reading your plugs correctly.

You'll want to dial in your primaries and secondaries seperately. First, disconnect the secondaries and concentrate on the primaries. Do a WOT run and turn the boat off without returning to idle. Remove a few plugs to be read. You want to read the soot line at the base of the ceramic insulator- not the threads. I believe ~3mm is optimal. More is too rich, less is too lean. Its easiest to read the plug if you cut off the threads so you can see. Do the secondaries once you get the jetting figured out on the primaries (assuming you convert to the metering block). Do the same procedure with the secondaries functioning. Reading plugs on the rear cylinders will give a better reading, as they are closer to the secondary circuit.