Mikeroc283

Im buying a pair of heads off my friend for $500. He has run them less then 1000 miles since he had his motor built and is changing up for a different top end. They are 49cc chamber heads all done up with 2.02 valves and summit rockers. I currently have 132250 miles on my car. Would swapping the heads out blow my bottom end up is my main concern?

RyanJB

We need to know more about what you have. More than just 49CC chambers. But just based on that I'd imagine your compression will be pretty high...

Mikeroc283

All i know is that he was running them on the 355 in his corvette. They have titanium valve springs. My motor is 100% stock except the high volume oil pump. I think he said compression would be around 10:1 or so

scamaro355

You need to figure out compression ratio for sure. Im running dart iron eagles with a 6cc trough piston .042 haed gasket and im setting (i think) .010 in the cylinder at TDC.. I say i think because im at work and dont have my notes in front of me. But it came out to 10.2:1 with a 64cc head. So a 49cc scares me. Lol

project89

iTrader: (1)

49 cc is going to need a piston with a huge dish




edit i jsst looked back threw my build thread

64cc chambers
10cc dished pistion 5 thou in the hole ,020 over bore
.015 shim head gasket
10.25-1 cr

lil high for my turbo motor but it works good

with the 10cc dish pistions and same gasket/deck clearance u would be about 12.5-1 cr with a 49cc head

Night rider327

iTrader: (13)

No, the will not work....

1st the 2.02" valves will hit the top side of cylinder bores on a 305 engine. 1.94" is about the largest you can go on intake valve size on a 305..

Next...

Those heads at 49cc will put you in the 10.5 to 10.7:1 compression range. It will not run on pump fuel. You would need 100-105 octane race fuel.

You could over cam it with a BIG aftermarket cam and 'bleed off' some cylinder pressure and get it to run on 93 octane but doing that will kill off your low and mid range torque.

You could mask that torque lose with deeper rear gears like 3.73 or 4.10's and a 3000 stall torque converter...

But know you rasied your powerband too high and the 305's tiny bores just can't flow enough air to make power in the 5000-6500 rpm range.

Mikeroc283

they are NOT 49cc heads i found out. they are 2.02 valves and are 64cc. Id like to throw them on my car this weekend but if i cant ill just use the carb and intake. the carb is a performace built quadrajet and a weiland aluminum intake.

scamaro355

Thats what im running with my s480.. I cant wait to see how it performs

Mikeroc283

Not putting them on the 305. Doing up a 4 bolt 350 i bought a few weeks ago and slapping them on if i dont they go on my grand prix.

Night rider327

iTrader: (13)

oh ok, they will work great on the 350

Mikeroc283

Right now i need some heads that will fit the 305 and give a little more power along with a carb that doesnt require a button for the transmission lockup.

Night rider327

iTrader: (13)

Thats the prob with the 305, not much choice for heads. Like I said before the 2.02 valves hits the deck/cylinder.

The only aftermarket I know of with the smaller 1.94 valves and smaller chambers is the trickflow heads and they aint cheap.

Other options are 305 H.O heads

Or L30 305 vortec heads but then that also requires the vortec style bolt pattern intake