I have a 78 f-150 with the 351m and I would like to put a new intake manifold on it and hop the motor up a little like with a cam and maybe some roller rockers and some roller lifters or something like that. but I would still like to keep it streetable and not do any major stuff like pistons just yet. but what I don;t know is what cam would work with the stock heads but still give a boost in power? thanks for the help. oh and I will probably be converting the motor to throttle body injection.

 

lots of info in the 335 engine section of FTE on this, also check.


351M/400 Performance Build Up

 

Moved to proper forum for advice on 351m upgrades.

 

thanks for moving my post to the right forum. my next question is will swapping out the cam for one that has more duration and lift improve my engines power and torque? or would my best bet be to swap out the heads? also how much lift and duration does the stock cam shaft have?

 

If stock an rv cam would work, a roller is nice upgrade, a 4bbl intake carb and headers would really do wonders for you...

 

which roller cam and roller rockers would work with the stock heads? I already have a 4 barrel carb on it.

 

Before you do all that, consider what you are working with. Your engine has low compression and a cam with more lift and duration will probably just bleed off more cylinder pressure from your already low-po motor and leave you wondering what's wrong.

Also, how many miles are on your engine? Are you seriously going to all the way into the cam and NOT put in cam bearings? And clean it up?

Read the link in the previous post. If you want performance, going 400 is really the only way.

If you stay 351m, imo you should limit yourself to a straight up cam timing set, dual exhaust with a crossover pipe, and maybe a small 4bbl.

All usable when you move up to the next level, which would start with a rebuild and the 400 crank.

jmo, ymmv, your money dwyw.

 

yeah I can see what your saying. my engine has 95,000 miles on it but It doesn't burn any oil how long do these engines usually last before they need rebuilt? I have been wanting to put a 4 barrel intake manifold on it but my engine has and egr valve on it I have a 4bbl edelbrock carb on it already and have dual exhaust so maybe I should look into getting a new manifold and headers.

 

With 95,000, I wouldn't put a thing into it. My opinion is from the negative side here, I'll be open about that, you could get more miles out of it and I could be wrong, but based on my personal experience, I'd do a rebuild. I put several hundred dollars into a 70,000~ mile 400 last winter, cam, timing set, headers, intake, carb, valve springs, it ran beautiful for about 2 months, and then I stepped on the gas one day and it tore itself in half. I spun out bearings, cam rod and main, and upon tear down, realized I had 2 crakced heads. Until just a couple days before the big failure, it wasn't showing any symptoms of having problems, running smooth and even, lots of power, no smoke, but it's a high mileage engine, and about 35 years old. Now I have to take the time to do a total rebuild, after already taking the time to do half of one. I'd either leave your 351 as is, trying not to tempt fate, or, if you definitely want more power now, at least tear the engine down, inspect the bearings, inspect the cylinder sleaves (measure for wear), and then make your decision.
Nothing wrong with that first option keep in mind, more power looked really nice to me when I thought it was going to be a week long project, but you have to consider the fact that tearing in and hopping up part of your engine can put alot more pressure on the rest of it than it's ever seen, so unless you're prepared to take on a month of engine work, I'd just wait for your engine to tire out, and do the big work then, when you need to anyway.
AleX