Combustion Chamber Size?

[Gregjc68]

Looking for Head specs for a 1977 L48 what is the head combustion chamber size?

 

[waterboy1976]

68cc I think....Im sure someone else will chime in here..

 

[Curtis]

More than likely if heads are original they will be 76 cc. mortec has some specs.

 

[waterboy1976]

Curt....you are correct...they are 76cc....... ....not 68...

 

[Gregjc68]

Thanks, guess I'll be purchasing new heads when I rebuild.

 

[waterboy1976]

Stock heads are decent if ported and decked (that lowers the chamber size) but a nice aftermarket head will work great when you match cam, intake, carb, and heads.....mine are Darts with 64cc chambers 180 cc runners and we are around 10.32:1 compression.. Higher compression equals higher power.....

 

[Gregjc68]

Idecided on going with a 383 stroker but haven't determined all the specs yet

 

[pgtr]

Good points. The pistons are typically dished on most L48s AFAIK. Before jumping to replacing heads what about replacing pistons - say flat top hypereutectics (I always forget how to spell that!) w/ reliefs?

Doh! nevermind - just noticed your post on the 383 route. Good luck w/ that!

 

[AKRAY4PLAY]

i'll bet you with 10 to 1 odds that you have 882 casting heads. if so, they are junk. the castings are super thin and do not lend themselves to porting or valve grinding without the chance of cracking. you can get some aftermarket heads that will flow better for less money than a port and valve job. unless you are running the stock heads for certain bracket racing, roundy-round classes or numbers matching purist approach, it does not make much sense to use the old stuff. there are tons of 383 combos and crate motors out there, and the Vette loves to have more power! build away and enjoy!

 

[USNA1969]

Idecided on going with a 383 stroker but haven't determined all the specs yet

Is the 383 derived from the 350? If so, is it done by changing to a crank with a longer stroke?

Thanks

 

[AKRAY4PLAY]

Is the 383 derived from the 350? If so, is it done by changing to a crank with a longer stroke?

Thanks

yes, the classic way of building a 383 is to take a 350 block and put a 3.75" stroke crank (same as a small block 400) in it and over boring it 0.030". the stock crank has a 3.48" stroke. there is another way of building a 383 but very uncommon. you take a 400 small block and destroke it. generally speaking, the longer the stroke the better torque you have and the shorter the stroke the more horse power you have. long stroke motors are generally low revving com[paired to short strokers.