engine performance

[bigyellowtruck]

hey guys just wondering i have a 79 f250 with a 400ci 6.6l i was wondering what i could do to the engine to make it a lil more snotty i allready have a edelbrok intake manafold and a 600 cfm carb i was thinking on the lines of a cam and heads? thanks

 

[5.0Flareside]

A cam is the best thing you can do as it sits right now... talk to Tim Meyers Inc...

Tim will set you in the right direction


http://www.tmeyerinc.com/

 

[LEB Ben]

Straight up timing...a cam with around .500" of lift, and that 4bbl setup isn't doing anything if you don't let the engine breathe...so get a set of headers. As for heads...you're pretty limited.

 

[bigyellowtruck]

ok yeah ive read theres not much to do with the 400 but im gonna try i see you got two of them?

 

[LEB Ben]

Yessir I do. There is lots that can be done for a mild to moderate build and for less than 3k you can wind up with 350-400rwhp and 450-500rwtq. Either have your heads worked, or there are a few aftermarket heads. The wilder you get with the heads, the wilder the cam and pistons can become. But I'd say those numbers are about the limit for a 400 besides strokers...but I don't really think a stroker is logical financially in a 400. Once you start talking strokers, I'd swap to a 460, but before that point, the 400 can be made respectable and comparable to 460.

 

[DNFXDLI]

Aussie heads are a good compromise between stock and aluminium.

 

[bigyellowtruck]

ok yeah i wasent looking to swap it the motor runs perfect nvr had a problem with the motor just looking to do some stuff needs a little more power to turn the 38" you no but deff will call up tim and figure out wat to do

 

[LEB Ben]

Quick question...whats the gearing like in your truck with 38's? If you're anything less than 4.88's...I'd bet your problem is more gearing than engine.

 

[bigyellowtruck]

i think i have 3.73 in it not really sure guessing with the 3 speed auto its a got a c6 tranny

the truck revs pretty high on the highway at around 70

 

[LEB Ben]

3.73's aren't stock, so they woulda had to have been swapped. And if they are in fact 3.73's, that's your problem. However, if you do actually 3.73's, you won't be revving that high with 38's...at 70mph, you're talking 2300 rpm...and typically that's the rpm you're looking for at 55mph.

 

[dragogt]

Regear and you'll get a lot of performance back..

 

[bigyellowtruck]

ok im sure the trucks drivetrain is completly stock its a dana 60s front and rear how could i tell what gear it has

 

[5.0Flareside]

oooo..........


it aint gonna be exact but watch the video in this thread i made..... it'll give you a really close idea of what it is...

http://www.fordtruckfanatics.com/forum/showthread.php?t=21797

 

[dragogt]

You've been waiting for that haven't cha...

lolol

 

[5.0Flareside]

why yes i have....

 

[LEB Ben]

Check for the axle tag, post what you find, check the warranty plate, post what you find...pull the diff cover count teeth and divide...jack the rear end spin on tire two full rotations if it's an open rear and count the number of times the dshaft spins.

 

[5.0Flareside]

Check for the axle tag, post what you find, check the warranty plate, post what you find...pull the diff cover count teeth and divide...jack the rear end spin on tire two full rotations if it's an open rear and count the number of times the dshaft spins.

or...... watch my video...

 

[LEB Ben]

^^^Isn't your video essentially the same thing as my last suggestion???? I still haven't had a chance to watch the vid. By your description, the only difference sounds like you're spinng the dshaft and counting tire revolution(s) and I'm spinning the tire counting dshaft revolutions.

 

[5.0Flareside]

yeah, but i say in the video you can do either.... but for me... if i spin the tire instead of the driveshaft it doesnt count right, but spinning the drive shaft for some reason is always dead on...

 

[dragogt]

IIRC Spinning the D-shaft works better when you have a L/S or locker..