I just bought a 78 F-150 with a blown 351M from a co-worker for $200. I went ahead and bought a remanufactered engine from a parts house, but after finding this site and reading the posts, I'm wishing I would have, built my own, due to the sluggish performance of the stock 351M . I'm going to add some bolt on performance items, remove the emissions control stuff, and wanted to get some advice on what would be the best options. I'm thinking about going with an edelbrock dual plane manifold, a 4bbl carb, and headers. I don't really want to change the cam, but I'm wondering if I might have to upgrade the cam and time chain inorder to see the performance in the other items? And if I do upgrade the cam, will I need to change the valve springs? Also, does anyone have an opinion about the edelbrock performance package (intake, cam, & carb) for the 351M?
The truck will mostly be used for weekend hauling and playing around.

Thanks and great website,

Matt

 

You might check to see how much compression you have before you start spending a lot of money on external parts. If it's a low compression motor like I suspect, it may not help much. I made the same mistake with a 390. Now I'm waiting to rebuild it with some real postons.

 

[updated:LAST EDITED ON 25-Jan-02 AT 08:53 PM (EST)]I would check the compresion and make sure it has at least 125psi per piston. But I run a 400 (just a stroked 351) in my truck and it lights up 33" tires in two gears and slams you in third at WOT. Yes you will need a cam to get anything significant because the cam shafts that came stock are very small lift and do not properly feed the engine. "Cleveland" engines have very well sized ports and valves so a mild duration high lift cam gives them great port velocities which build great throtle response and killer torque and great midrange power(for leaving most anyone eating your dust in passing gear!). Yes you will need to change the springs and lifters, but most companies sell them as a matching package. The performance numbers on mine are 380hp and 500ftlb torque all of which are in usable rpm ranges. I run and edelbrock performer manifold, edelbrock performer RPM camshaft and roller timing chain, (I ported and polished my heads you don't have to do that), roller rockers, holley 750cfm( use the 750 it does make a difference I had a 600 and my 750 blows its doors in in low end and especially midrange remember these engines have large valves and will use all 750 cfm if you have a cam)and ported and polished exhaust manifolds/w 2.5 dual outs, hi-pro wires and cap, stock ignition. I have a few internal mods like pistons and stuff nothing major or wild but it isn't hard to make 300hp with these motors at all. Though a 2" carb spacer makes a significant throtle and off the line improvement believe it of not. Here is an example I know that my motor is good for another 30-40 hp without getting inside.

400m

 

im thinking these mods are safe. you can get an aftermarket intake and get a 650cfm carb, then get aftermarket headers. if you need more, id look at a complete rebuild, as suggested, i would add that since the difference between the 351m and 400 is just pistons and crank, get a 400 rebuild kit from paw.

 

I run a 351 cleveland bored and stroked to 400 with aussie heads that have been ported and polished and milled. MSD 6AL with 8.8mil wires and a msd super coil, roller rockers, King Demon 1050cfm carb on a high rise intake manifold. All this cost me about 1500 dollars (most of which i got on ebay) but it now has a hp rating of 487hp at rear and 610 pounds of torque. My 3600 pound stang now has a et of 10.13 at 142mph.