stevieturbo

Spec will be 382, Callies Rods, Ross Pistons, ARP studs throughout, GM MLS gaskets, Vortech YSi, 224/230 on 115+4 0.581/0.591, 1.7 YT rockers, 1 3/4 LT's and dual 3" exhausts
UK 97RON fuel ( Roughly equivalent to US 93 octane )
M6

Will probably add a Snow kit at some point.

I was going to re-use my FFHP heads, which would have given me 9.0:1 CR with 62cc chambers

I have just ordered a pair of ported Edelbrock 215's from Andy at A&A with 66cc chambers.

This should drop me to around 8.7:1

Should I mill the heads back up to 9:1 or leave them be at 8.7:1 ??

I want to make as much power and torque possible with the above combo.

Race fuel is not an option, although adding 100% Meth via a Snow kit is. Pump fuel is expensive enough here.

What CR should I go for ?

67Ranger

iTrader: (16)

8.7:1 would be better, i think. Milling the heads probably wouldnt be good either, since if you are running higher boost, you'll need the extra deck height.

ddnspider

iTrader: (26)

id like to know what kinda dish are on those pistons that he's got a 9:1 CR with 62cc heads

JZ 97 SS 1500

iTrader: (2)

Go with 8.7.

JZ

fastlt1

iTrader: (4)

Why not 7:1 or 8:1?

stevieturbo

With the 346, they were 16cc dish.


The new pistons for the 382 have 25cc dish. Quite big lol.

Slowhawk

iTrader: (12)

Matter's on the boost level.I would say probly 15-18lbs which I'd run no lower than 9-1 compression and possibly run 9.5-1 compression to kick up the midrange.You can do this on pump gas easy enough. Blowers like compression and respond to it unlike Turbo's.

kp

iTrader: (34)

Theory has it if you have a big enough blower/turbo to lower the compression more. If you are maxing out a small blower you are losing power by dropping the compression too much.

The YSi will move plenty of air, I wouldnt sweat it either way..

stevieturbo

I know the YSi is a big blower, but I was concerned that with the larger engine, better heads etc, it might not make enough boost to make a lower CR worthwhile.


With the old engine, it was making around 16psi at 6200rpm, thats spinning the blower at around 56,000rpm.
8.25" crank, 3.15" SC.
I'll be dropping the blower to 3" and upping to 12 rib ( belt wrap isnt great ), and probably revving a bit harder next time round.

Revving/shifting around 6200/6300rpm just felt right.

kp

iTrader: (34)

I dont think the .3 or so will make a difference either way. I assume its a 4" stroke by looking at the piston pin so I dont think low/midrange will even be an issue. I'd probably just leave the heads alone and take the 8.7:1.

Wet 1

iTrader: (4)

I totally agree.