So a set of 852s that were cleaned up and milled would be better?

 

honestly 241 heads were one of the worst heads made. They don't even flow better the stock truck heads. If you want to replace the heads, buy a pair or 243s..


241
Chamber 66.67 cc------0.100--0.200---0.300---0.400---0.500---0.550--0.600
Intake 200 cc------------67----122-----178-----215-----219-----223---227
Exhaust 70 cc------------52-----97-----133-----156-----170-----176----180

706/862
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174

 

just buy a set of 243s and mill them to 59cc that should do the trick the stock 852 heads are 61cc iirc

 

definently. thats what i had on my 4.8 (rip from friday) and it went 13.5 with no timing and 11.83 on spray...

 

YOu could even mill the stockers to get the static and dynamic compression up. Cams love comression...

 

I wanted to bring this back up for several reasons. One I wanted to thank everybody for the advice on the 241s. Now I've picked up a set of 852s and I'm having them milled and using a thinner head gasket to bump the compression to 10.5:1. Two is to see what y'all think about the valves. There's nothing wrong with them, but the heads have 120k on them. Do I need to have new valves put in or will the existing ones be ok?

 

Depends on the cam...cams with a lot of overlap love compression....


Good advice here, just to add, I'd up the converter choice to about 3600 considering the size of that cam in those little cubes...

 

No opinions on the valves?

 

They'll be fine. People have put twice that many miles on stock valves with upgraded springs and high rpm...

 

Thanks for the responce.