hey i have a 91' z28 and i am just seeing if there is any way to make it "streetable" at all? 13:1 compression now... any way to make it way lower and run smooth on pump gas? engine specs are as follows...

Dart 400 Block
Brodix Heads
Series steel crank 4340/3500 stroke
pistons are forged aluminum dome
keith black .080
six inch bullet connecting rods
titanium valves .080 bored
intake : 212. exhaust : 1.60.0
Pushrods: 7994 Competition cams
7.950 .080
lifters are full roller competition
cams and cam is full race competition cams
rings pro/series molly file fit
rocker arms aluminum full roller : 1.52
oil pump high colume / 7qt pan
13:1 compression
MSD-7AL-2 Pro-Race
MSD blaster 2 coil
msd programmable timing computer
1000 cfm carb



any ideas? if it is not a possiblity i have a friend that is selling a complete Lt1 from a 96 or so firebird for cheap that i may swap in.... thanks for any help.

 

To lower the comp you could pull the heads and relieve the chambers some, do not
use a thicker head gasket to increase vol. You'll lose quench and actually be MORE detonation sensitive. If your cam is REALLY big, (like,umm 270@ .050 and LSA of 110 or less) you can get away with 13:1 on pump gas, esp if you're running alum heads. Just watch it when your standing on it!

 

bump

 

 

For the cheap, I say NO WAY. For some new slugs, smaller cam, smaller carb and a few other minor things you can swing it.

Or you can run it on the street as-is, lower the timing, don't let it idle for long periods, stay on top of valve spring pressures, run good pump gas, stay out of the throttle and you'll be fine for a while.

 

212 duration on the intake is really mild for a 400 engine. You'll have a ton of cylinder pressure at low engine speeds. 13:1 is also really high for a pump gas engine. 11:1 is pushing it on 93 octane. You need to change the pistons, in my opinion. Or change the heads to something with a larger combustion chamber (76cc or higher).