Hi i am working on my 77 f150 i have a brand new stock 351 M trying to get a little more power out of it so i bought a set of 4BBL Cleveland heads and intake to put on my 351M hoping to get more power ,will me hooker headers off my 351m bolt on the Cleveland heads? is there any thing else i might need to change on the motor ? any info Thanks Shane

 

what cam should i use i do some off road ,towing ,burn outs lol

 

I think the headers will bolt on, but the ports on the 4bbl heads are larger, so there will be a mismatch between heads and headers.
I thought the 351M used the same taller, therefore wider, block as the 400. If that is true, and I'm certain it is, the 351C 4bbl intake won't fit. It will be too narrow. I think there used to be adaptor plates to fill the gap, but I don't know if they are still available.
Do the pistons in a 351M accomodate the larger valves of the 351C heads? I don't know, but I can't remember that being a problem.
I'm going by memory on things I kinda knew 30 years ago.

 

Summit carries the intake adapter plates, but for the life of me I don't understand why you are using the Cleveland heads? I am not being nasty or anything eles but IMHO those heads make All their power in the upper RPM band way above the 351M/400 range. I would stick with the stock heads and do the standard mods, save the BIG heads for something else. John

 

Oh, an BTW I am building a 77 351M also. I can give you some helpful insite as can a lot of others on this site and will help you if you would like. Just e-mail me at popajon@tnt21.com

 

I saw you said off roading does this mean you have a 4x4? Popajohn is right cleveland heads make power higher up in the RPMs. Instead of a cleveland intake just spend the 189 dollars at summit or jegs for the Weiand intake manifold for 351M/400 engines. Its a really good manifold. Now whats your truck gonna be used for? You could still use the cleveland heads cause its will bump up your compression ratio which is serverly needed on these engines and you make some power down low it will just really throw the power on a little bit higher.

 

The compression ratio bump will depend on which version of the 4bbl heads you have. The '70-71 heads will raise it more than the '72-74 4bbl heads.
I don't know if raising the rpm range where the heads raise the power is anything to be concerned about. The 4bbl Clevelands were the hot ticket in drag racing and even NASCAR for a time, but they were also strong street engines. I think the 351C 4bbl heads allowed for high rpm power with proper engine modifications without killing the low rpm power. I had a '70 Cyclone with a stock 351C 4bbl for a short time, and it was a lot of fun to drive. A really nice, balanced street package. I just bought the car to resell, which is why I only had it for a short time. I also drove a '74 Ranchero for almost 30 years with a built 460, and I owned a '70 Cyclone 429CJ, so it's not like I didn't have anything to compare to. However, if you are 4 wheeling using huge oversized tires, the higher rpm range of the 4bbl heads may come into play. It's really going to depend on your entire package - heads, cam, gears, tires, etc. The increase in compression will no doubt help.
My 460 was built before many people were building them, so we had no help. Fortunately, my mechanic chose all the right parts and it worked well. You can draw from a lot of people with experience. Listen to those who have done what you're wanting to do.

 

X2 on that info 429CJ-3x2. You have to know what you want your truck to do THEN do your planning and stick to it. I beleive that changing your plan half way through or wanting your truck to do everything ( lots of RPM, a torque monster 30 MPG ) is wishful thinking and a waste of hard earned cash. Have a plan, listen to people who have done it and you will be a happy camper with a great toy. John

 

Thanks for the reply i had the 351M Redone (Stock) in my 4x4 truck but its a gut less wounder lol i put on and Edelbrock intake and carb opened it up a little , so i wanted to get a little more power out of it, my brother has a 75 Chevy 4x4 i kill him in towing but his truck flys down the road lol i hate Chevy, so now im try to do some changes read that changing ur heads to Cleveland 4BBL heads will give you 50+ horsepower and not lose of towing power , so i bought a 351 Cleveland motor out of a mach1 has 4bbl quench heads gonna sell the rest of the motor , Thanks for your Help guys

 

only paid 300 for the 351C motor LOL

 

If I where you I would go thru and make sure that cleveland is ok then drop it in your truck. Thats ALOT more powerful than your 351M

 

I thought about that but it needs rebuilt has not been run in 20 yrs or more and i just put $4000 in the 351 motor i paid way to much from the ford dealer , it would cost a lot to redo that engine but it has 11 to 1 pistons in it lol

 

So why not keep the engine and rebuild her over time? Those engines are really hard to come by.

 

sounds like you have the quench heads. what is the casting numbers on you heads. I'm building a 400 ford with cleveland 4v heads and check into wyoming 400 4v on this site. Also do a compression test and tell me what your compression is. will help the best we can. Call tim meyer for adapter plates or check into pricemotorsports are who actually build them. Or check into MPGheads if near colorado area. scott does some good work.

 

ran the cleveland and ran great. high compression with dome pistons and a 268 comp cam. great little 4wd setup. but the 351m doesn't have much compression and hard to compare either if compression isn't the same. On the 4v heads I would build a 400 motor instead of 351m. big heads need some cubic inch. If you go 351 cleveland the headers will be the issue for you applicaiton and gonna need to get a different flywheel housing for small block or small block c-6 tranny auto. really like the cleveland motor. but the 351m will run well also if same effort is applied.