Pat 69BigBlock

Rebuilding my 427 L36 engine and want to get an idea of HP and Torque figures. Probably won't be much more than stock, but here is the info.
Bored 30 over with stock intake and exhaust manifolds. Original Quadrajet carb to be rejetted. Stock heads with porting (2.19/1.88). Compression
ratio 10 to 1. Keith Black Pistons,Comp Cams extreme energy cam 11-242-3. If I am leaving anything out let me know!
Thanks,

1979toy

What type of heads are these? oval or square.

Could you define your porting?

Are the valve pockets ported?

Pat 69BigBlock

I'm not sure I can answer all of your questions.
The heads are stock L36 heads oval ported with valves enlarged to 2.19
intake and 1.88 exhaust. As for the valve pockets I'm not sure. I do know that that they have done something to accomodate unleaded gasoline.

Flareside

Every time I run my L36 configuration through Desktop Dyno, I come up with 300-320 hp. Unfortunately, my 1/4 mile time also confirms these numbers (14.6@96). I have no idea where Chevy got 390 from :confused:

I ran this with "290" casting heads, which is what you should have.

Anyway, when I plugged your XE268 cam and bigger valves in, I came up with 360HP at 5000 rpms. Headers would take you to a bit over 400 HP with that cam, but I would run a hotter cam with them for even more power. The good part is that torque is flat from 2000 to 4500 rpms at around 470 lbs. Should be a lot more impressive "seat of the pants" than it is on paper. Your engine may make a bit more power due to the porting work.


[Modified by Flareside, 7:48 PM 1/15/2002]