joshh44

howdy.
i just recently got a hold of a 2 bolt main, 454 block.
im going to build it into a high output engine for my camaro.
my questions are.

what is the biggest overbore you can get safely?
im just looking threw this website.
http://www.roadsters.com/bbc/

i would like to stroke it out to a 496 cube motor.

i wouldnt mind getting a 4.500" stroke crank but im fairly new to the big block family.

AlkyIROC

Factory BBC blocks can safely go .060" overbore. Aftermarket blocks can go .120" over.

You're not going to easily fit a 4.500" stroke crank into a factory block. 4.250" will fit. Usually anything bigger than 4.250" stroke is for aftermarket blocks.

joshh44

oh ok thanks for the info. that was all i needed.
well that question is out of the way. lets try another one.
what is the difference between oval port and rectengular port heads?

AlkyIROC

The size of the intake ports into the heads. Unless you're spinning the engine close to or over 7000 rpm, you don't need rectangular port heads. The larger ports allow more air into the engine but also decrease the velocity of the air entering the cylinder. A very high compression engine can use rectangular port heads better than a low compression engine. Mine is 13.4:1 compression with rectangular port heads and I shift at 7600 rpm.

A good set of 781 or 049 oval port heads fitted with 2.19/1.88 valves and some basic pocket porting will provide more than enough power.

joshh44

ok so rectengular port heads are more for higher compression engines?
im looking into some alum. heads for the engine and i cant decide what i want to get.
what size of valves would be a good size that isnt overkill?

i found some heads that dont look to bad.
http://www.jegs.com/i/JEGS/555/51465...87#moreDetails

is this head more for an aftermarket block?
im going to be stoking the 454 block to a 496.

AlkyIROC

I have Canfield heads on my engine. Those Brodix heads are almost identical to what I have. They'll feed a 496 with no problems although they are rectangular port heads. Mine are feeding a 540 although they're a little small for my 540 but they provide enough power for what I want to do. I could use some 345cc or larger heads.

That $1050 price is for one assembled head not a set.

Without knowing what induction system you want to use, camshaft, gears, tires, transmission, vehicle weight etc, it's hard to suggest a specific head.

AFR makes a good head

joshh44

yeah i was looking at the price. it got me thinking would it be better if i bought a set of cheap bare heads. port them. and assemble them myself? i got all the tools to put them togeather

ill just list out some parts im putting on the car.

9" rearend with 4.11 or higher gears, TH400 with transbreak, some MT drag tires. im not to sure what size tho. maybe a 28" tall tire.
my car will probably be around 3000 lbs. maybe alittle more.

it is hard to say what would be a good head for the engine.

i dont know what cam ill be using. i should find a cam that will work with the head for the best combo.