hey im rebuilding a 400 ci for my car and i am wondering what could be machined on the block, heads, or intake that could give me more power befor putting it together again, i work in a machine shop so i can do everything myself, if some of you have tips or tricks, it would be really helpful

 

if it isn't done already, make sure you drill steams holes in your heads. sbc 400s were notorious for warping/cracking heads due to lack of cooling, but the steams holes fixed that. you can find the locations for these holes just by using google.

you could bore your cylinders out for a few more cubic inches, but that won't give you that much more power. this is done mainly to give you a smooth cylinder wall free of scrathes and scores that may have been left behind.

as far as machining for more power, milling the heads down for a great compression ratio is the best bang for your buck. the trade-off though, is not milling them too much that you CR is too much for 93 octane pump gas. here's how to calculate CR:

http://www.carcraft.com/techarticles...tio/index.html
and
http://www.rbracing-rsr.com/compstaticcalc.html

lastly, a great power addder is porting and polishing the intake/exhaust ports and combustion chambers. i don't know what kind of shop you work at, but some shops have people that are trained to do this and shouldn't be done by an amateur unless you can pratice on some scrap heads first. hope this helps and good luck!!

 

Other things you can do to the heads are port match the intake and exhaust inlets & outlets for better flow transition from both the intake manifold and exhaust manifolds. Lets not forget bigger valves too. At the least you should go with 2.02 on the intake and 1.60 on the exhaust, these are the typical and most popular upsized valves for a SBC. Don't forget the 3 angle valve job job while you are at it. If you port and polish the heads yourself keep in mind flow is more important than size. Bigger does not always equal better when it comes to head ports.

Those are some of the typical things that have been done to heads for years. But if you have the money to spare, just get a pair of aftermarket aluminum heads. You'll be able to run a higher compression ratio than what a comparable set of iron heads would allow for. That, and even the best head work on old iron heads will be beaten by untouched modern aluminum heads.

 

what heads are you going to run? what casting numbers are they? from my experience now a days its really not worth messing with the factory stuff. you can get aftermarket heads for a good price and theyre probably going to flow better then what your working with. aluminum heads are nice and theyre cheap itll cut some weight off of the nose but iron heads are cheaper and just as good. if i were you i would run a set of iron heads that are already drilled for the 400. you can also run pretty high compression and timing and not ping. heres a useful site you can look up your heads and block and what not and find out what they came off of. goodluck.
http://mortec.com/