Need More Big Block Help!

[7d9_z28]

ok, my heads were sitting next to another set of heads... and they were confused... my bad...

so my heads that came with the 402 i bought, are the stock 6272292 heads.

ive been searching the net, looking for original 67-72 big block heads to bolt on that will give me more power and higher compression. but as is the way of the net, i get conflicting stories. "oh yeah those heads are perfect for your application!"
"no theyre not dont listen to him!" :takethat

so i come to the gods of old chevy info (thats you guys!) for help

ive come across a set of copo 427 camaro heads for a good deal.. but some people say that they ( casting 3919840) are a rect. port thats too big to run on my 402

ive also found some #-049 and #-063 heads.. similar stories some had good luck some had bad luck

i dont know what to do! its a street car. ill do burnouts, ill cruise, ill do 130mph if i get on the highway. probably not in need of a high winding engine. what do you guys think?

 

[walkerheaders]

closed chamber OVAL port is what i would do. a clean set of springs, valves and seals. maybe some roller rockers and poly-locks.
a 402 will have about an 1/8th inch high dome on the piston. this is perfect. some moly rings, a roller timing chain, medium-large HYDRAULIC cam, torker OVAL PORT manifold and a 750-800 vacuum secondary holley. will make a very respectable, affordable, reliable tire fryer.

search and get yourself a copy of "how to hotrod Big Block Chevys" that book is so old, the 402 is still fresh.

 

[7d9_z28]

thanks

i TRIED to get that book but couldnt find it and didnt want to order it... i had read the small block version of it and liked it

i do have a book i just got called "How to build: max performance chevy rat motors" its alot newer but talks more about the aftermarket, i want to keep original-ish parts, preferably with some era speed equiqment (vintage big block parts are PRICEY! )

i know closed chambers are the way to go, your suggesting keeping the stock pistons?

what causes the oval ports to be better than rectangulars (in this case)?

would it be fine to keep the stock springs and rockers for now? (im not rich... im 19 and work in a factory)

are there any particular head casting numbers you can recommend? i have a list but if theres some better than others it would be handy to know!

thanks!
alec

 

[7d9_z28]

i forgot to mention, i havent checked but i believe the previous owner said he had just installed a brand new timing gear drive setup (which i had planned to run in my 355) is there much of a difference between gear and chain? i hear gears are more precise for timing, but im not sure about reliability...:?




looks like i have ALOT of : research and reading to do

 

[Don Jacks]

I would have to ditto Bob.s[walkersheaders] build.John Lingenfelter used the 049 castings,with big valves and a little port work on the exhaust side,on a street 496 and made SICK hp and torque .Sold it as a crate motor.So much for internet nay sayers As to valve springs,ANY cam larger than stock MUST be used with proper springs.I can relate to the "fundsrlow"condition,but stock springs are a no-no.At 402 inches,this motor is small,so retangular port heads will put a hurting on your bottom end.Build the motor as Bob suggested with a modern Comp Cams or a Luniti VooDoo seres[about 274 advertised duration would be fine],The Torquer single plane,shoot for about 10.25-1,Small [1-7/8 th in primary tube] tube headers,and shift it at about 6000 rpm when youre on it hard]This thing will pull hard to about 55-5600 rpm,and with " decent "parts will live for years.The heads he suggested can be found on just about any 325 -360 hp 396 form 1966-1970.In 1971,they started the low comperssion game so the larger chambers require a bigger dome to get your compression back.I dont like gear drives[unless factory] for durability and noise issues.I want to hear my cam,not something making noise just be cause it can.Torsional viberations transmitted to the cam is another negitive,but on a motor at this power and rpm level,I doubt you'd be able to measure any differance in power.