HI, I need the help of a 400 expert. I recently bought a 77 f-150 with a 400 that was not original, but out of a car. I did some suspension work and bought some tires and i am running it in the local mud races. When i first got the truck, the owner told me that it held low oil pressure when warm and he suspected that the timing chain was leving chunks in the oil pump pickup. So i bought a new oil pump, pulled the pan, sure enough, timing chain chunks. I replaced the oil pump and it does still loose pressure when warm, it runs about 20 psi warm. but the motor runs great and has lots of power. Now for the question. In the class i race "stock" the rules for engine mods are this, you have to have stock bottom end (pistons, crank, rods), no porting of heads, no aluminum intake and the intake has to be stock availiable for that truck that year (which leaves me with a 2bbl) and it has to make at least 17.5 inches of vacuum at 800 rpm. I plan to redo the top end this winter. By top end I mean cam and carb since thats all i can modify. I am also on a very low budget, and this is all i can afford. What I want to know is if i got a cam in the 250-260 range and a 500cfm holley would this motor make some good power. keep in mind i need low end because you cant have any stall of any kind. What do you think the best way to set this motor up is?

Thanks for all your help,
Matt

 

O ya one more thing, the biggest cubic inch you can have in stock class is 368, but the 400 passes for a 351m pretty easy since the only difference is the crank. Shhh dont tell.

 

ooooh- you little stinker!. I'm no expert but will respond with things i've learned from others as I am in the middle of tearing down a 400 to build. I would look at increasing compression any way you can- shave what you can and skinny up the gasket. I doubt that you will be able to do anything substantial except carb it with a 600. cams usually require matching valve springs etc so you might be able to get away with a crane 255deh since your not looking for it to last long anyway.

I doubt others would care too much that you have a 400 cause with the limitations placed any decent v8 will kick it's fanny. I'm curious why you would break one rule and draw the line not to break other rules that would never be found out do to the 'honor system thing'. The only real benefit of the 400 is the low end torque which is better than some motors.

I wish you luck in finding your path within the rules- not judging you- have fun.

 

You should look for a set of 351C-2V heads (75.4cc). These will give you more compression than the 400 heads, and will flow better without porting. Better yet are Aussie heads (58cc). These will raise the CR to 10:1.

The best cam to run would be a hydraulic roller, with specs like the 255DEH. The HR will give you more lift, without increasing the overlap that hurts the vacuum. This will cost more than a flat tappet cam, and you will need new springs and other parts to make the conversion.

 

I kinda had my heart set on a comp unit, 255/263 dual pattern, this comes with a timing chain which is in need of replacement too, the grind is abou tthe same as the crane on isnt it. As much as id like to find some high compression heads i think ill just leave the heads on, god knows i cant afford a new set of heads and i would like to save the hassle of of taking them off and putting them back on. this cam with a 500 cfm carb will be a decent combination wont it?

 

this cam is hydaulic flat tappet but that will still get rid of the overlap wont it?
and by the way thanks for the help so far. and to answere your question roger the only reason i c*eated with the 400 is because thats what the truck had when i bought it and i didnt have the time or the money to swap a different motor in. plus i know the 400 is nothing special, its really no better than a 351m.

 

Yes, a Comp 255DEH is 255/265. It will not have much overlap, but the lift isn't great. Some of the Crane units do give you more lift, but watch the IVC spec. The earlier the IVC angle the more low end torque you will get.

The 400 is a torque monster and will crush any near stock 350s at low RPM.