Milling Gen1 heads?

[jp]

How much is recommended to mill of a Gen1 head?
Or, what is the distance from the top of the piston to the deck top on a Gen 1 block?

 

[Vipermed 97.01]

JP milling your heads depends on what you want to gain from it,do you want to raise your compression or do you just want to resurface,if you want to raise your compression make sure that is the way you want to do it,are you using 1.7 rollerockers,what size pushrods,what is your cam profile,are you using stock pistons, with everything stock you can safely go .040 which should bring you pretty close to 10:1 compression.

 

[joe117]

Can you go to 10:1 and still use pump gas? If so, anyone know what kind of hp increase that would give over stock?

 

[99 R/T 10]

milling .040 may bring up Gen II to 10:1 (stock 9.6), but the Gen I would take more because of the stock compression is 9.1, right? Not positve here.

 

[HP]

Even thought there are reference numbers for a stock motor - any changes you
make - like porting, piston changes, and even head gaskets - will change your
numbers.
If you still have your motor together - or when you get your motor back together - there are formulas that will tell you exactly how much to mill the heads to get your compression to what you desire. It would be a good idea to record these numbers and
cc your head volume, for reference and to check on uniformity.

 

[Doug Supercharged Vipers]

milling .040 may bring up Gen II to 10:1 (stock 9.6), but the Gen I would take more because of the stock compression is 9.1, right? Not positve here.

Correct, pehaps even more.... I estimated your compression would go from 9.1:1 minus .040" will increase your CR to (approximately) 9.84:1.

Compression Ratio Formulas
GV (Head Gasket Volume) = Bore(in) X Bore(in) X 12.87
X (Head Gasket Thickness in Inches)

DV (Below Deck Volume) = Bore(in) X Bore(in) X 12.87
X (Inches Below the Deck)

HV (Head Volume) = CC's


VV (Dish, Valve Pocket, Dome Volume) = CC's
(Minus for dish or valve pockets, Plus for dome)


PV (Volume displaced by Piston) = Bore X Bore X Stroke X 12.87


Compression Ratio = (GV+DV+HV-VV+PV) / (GV+DV+HV-VV)

Cubic Inches = Bore x Bore X Stroke X Number of Cylinders X .7854

Convert Cubic Inches to CCs = Cubic Inches X 16.386
Convert Cubic Inches to Liters = Cubic Inches X .016386

Engine in Liters = (Bore(mm) X Bore(mm) X Stroke(mm)
X Number of Cylinders X 12.87) / (16386 X 1000)

Engine in CCs = (Bore(mm) X Bore(mm) X Stroke(mm)
X Number of Cylinders X 12.87) / 16386

Convert CCs to Cubic Inches = CCs / 16.386
Convert Liters to Cubic Inches = Liters / .016386

 

[jp]

We use the stock pistons, but with non stock piston rings. 1:7 Rockers, pushrods to be decided, Camshaft with mild lift 0.585. I'm just curious to know, since We are doing the heads I thought that I maybe should mill the heads to gain some compression.

JP milling your heads depends on what you want to gain from it,do you want to raise your compression or do you just want to resurface,if you want to raise your compression make sure that is the way you want to do it,are you using 1.7 rollerockers,what size pushrods,what is your cam profile,are you using stock pistons, with everything stock you can safely go .040 which should bring you pretty close to 10:1 compression.