351w questions/need some ideas

[GilroyRacing]

I have a 351w that is currently in a 78 Ford Truck.

The block came out of a 77 Ford Van. It currently has a set of heads off of a 1975 Ford Van. The block has been bored 30 over. and I believe it has been decked as well. The bottom-end was rebuilt using a rebuild kit for a 69 351 so it would have flat top pistons. It also has a stock truck cam.


I am thinking about pulling it out and putting a new set of rings and bearings in it. I am also thinking about putting it in my vic.

Do you think I should keep the same heads on it? Also should I stay with the same cam?

I am going to use a ford 4bbl intake, and a ford/holley 4bbl carb.

[1987cp]

Here ya go ... pick one of the following and install with stock 5.0 lifters and retainers:

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=894&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=895&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=896&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=897&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=898&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=899&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=900&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=901&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=902&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=903&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=904&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=905&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=906&sb=1

http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=907&sb=1

Probably stay with one of the smaller ones like the 413 with a factory 4V intake. Personally, I'm thinking very seriously about the 421 for my 351 ... looking so far like an easy 300hp with the E7 heads that are one it and as much as 400hp if I ever get the heads ported.

[Mercracer]

The bottom-end was rebuilt using a rebuild kit for a 69 351 so it would have flat top pistons. ..

Are you saying that you believe or that you know that it has flat tops? Only the 69-70 4V motor had flat tops.

[GilroyRacing]

i know it has flat tops

[Tiggie]

Get teh casting number off the heads. If you're running flattops on a 60cc combustion chamber and a decked block, you'll have some nice compression going on.

I don't have specs handy on the truck cam, but I'm sure it's a low-end torque grind. Stay mild on the cam choice for the best combo with your head and intake choice.

[GilroyRacing]

I completely forgot to get the casting numbers when I was up in Pa. When I go back up there I will def get the casting numbers and pst them.

[Pirate]

Well, IF it was rebuilt using 1969-1971 flat-top pistons (not 1970, and I will explain why in a moment), with their intended use to be installed into a 1969-1971 block, then you have a serious problem, as some doofus engine builder didn't do his homework.

First of all, if you are running a 1977 block, with the 1969-1971 pistons, your compression ratio is going to a crappy 8:1 or so with those heads, due to the fact that there is a difference between the 1969-1971 351W blocks, and 1972-1997 351W blocks; the deck height. 1969-1971 blocks had a 9.480" deck height, while the 1972-up blocks were at a 9.501 deck height. What this does, to summarize, is if you have the earlier pistons in the later block, the piston won't come anywhere near the top of the block, it will sit .019" in the bore. That may not sound like a whole lot, but depending on the quality of pistons used, it may be closer to .050" down in the hole, as only higher-quality Hypereutectic and Forged pistons are usually the only pistons that are close to zero deck height when installed; most 'rebuilder' pistons are never close to zero deck height (piston flush with the top of the bore, which is what you want)....anytime the piston sits that car down, you lose quench (where the air-fuel charge gets squished into the combustion chamber at TDC, vital for a clean burn) and cranking PSI, which kills power, 30-40 hp or so for every point of compression lost.

THAT is why it's crucial to learn what's in the guts of the motor.

[1987cp]

Eek, 8:1 would suggest peak torque barely over 300 lb-ft; no point in running a 351 at that point.

What's the rest of the story about 1970? '71 was the year for the "Boss 351" Mustang, I think ... though I guess that was a modified Cleveland engine and not a Windsor, so it's probably not relevant to the discussion.

[Pirate]

Eek, 8:1 would suggest peak torque barely over 300 lb-ft; no point in running a 351 at that point.

What's the rest of the story about 1970? '71 was the year for the "Boss 351" Mustang, I think ... though I guess that was a modified Cleveland engine and not a Windsor, so it's probably not relevant to the discussion.

Nope. Only a 351C 2V and 351C 4V Cleveland that year, along with the 351W in select cars.

[Mercracer]

The only car which had a Windsor 4V in 1970 was the Shelby GT350. Windsor 2V motors were found in other models in 1970.

[GilroyRacing]

I will know for sure when I pull it out of the truck. I will post up the real specs of the engine.

[GilroyRacing]

Here are the only numbers that i could find on the heads......


6D21 WCP 351 75

[1987cp]

I want to say those numbers are on the outside of the heads, and tell when that head was manufactured. The casting number is on the underside, right by the pushrod holes, and that's what'll tell us for sure what you've got.

[Mercracer]

1976 Vehicle Production year and year of casting.... Smog heads.....

[1987cp]

Yay smog! So will those probably have a typical compression ratio above or below the 8.3:1 I found for a '79 351W?