Flyinace3

I am planning a 383 stroker build this winter. What way is the preffered method to create the compression ratio I want , 10.5 -10.75. Using a smaller combustion chamber with dished pistons or flat top pistons and a larger combustion chamber?

1 deck height .025 in hole
Head gasket .015
Quench =.035
Cly head vol =70cc profiler 210cc
Piston volume 4cc f.t 2vr forged
6" rods
286 adv due can on 112 centerline
93 octane
Static comp 10.51
Dynoc comp 7.98

2 deck height .025
Head gasket .015
Quench .035
Cyl head vol 64cc profiler 210
Piston volume 8.5cc forged dish top
6" rods
286 adv due cam on 112 cl
93 octane
Static comp 10.68
Dynamic comp 8.11

TedH

When I researched compression options, I chose to step the combustion chamber down from 76cc to 72cc (yes, I know, not that big of a drop) to arrive at around 9.0CR. I compensate the low CR with lots of advance on the ignition curve (no detonation).

If it were me, I would go with flat-tops (with valve reliefs) and a 64-65cc chamber. If you can afford, go with aluminum cylinder heads.

Unless you are running racing gas, I'd keep CR closer to 9.5-10.0. I read for every 4cc drop, you increase CR by .5. So, if you have 76cc with 8.5cr dropping to 64cc should get you in neighborhood of 10.0CR.

If you really want to boost above 10.0, then you could use the thinnest cylinder head gaskets, shave the cylinder heads or consider a small dome on the pistons you install.

REELAV8R

Well you'll likely get the full gambit of answers here. IMO and the research I've done you would better served getting smaller chambers and D dish pistons. The dish allows better flame propagation than a flat top and the D shaped dish still has a quench pad vs just the dish piston.
Those heads are aluminum so running the DCR up to 8.2 or so should not cause problems if you cooling system is up to par.
I would want a tighter Lsa on 383 build. More like 108 or 107 assuming this is a power effort and not a daily driver.
Have you found pistons that will work on a 383 with a stock 9.025 deck. I don't recall that being available and still get the proper compression height for a .035 quench.
Running your given numbers a 285 cam on a 108 would net you a 8.2DCR with a 10.4 static CR.

Flyinace3

The pistons I found are probe srp forged that have a 1.125 comp height with a 6" rod they should be .020 in the hole and a .015 head gasket puts me at .035 quench. ?
My car is a 1980 4sp, 3.73 gears. I drive it on weekends car shows etc. I don't plan to ever race it, but I'd like to be able to run with the newer muscle cars. With my stock L48 and stock 3.08 gears l run 15.56 @ 87mph I'd like to get in the low 13's

MelWff

does that cam work with stock stall speed and a 3.08?

Flyinace3

I am also changing rear gears to 3.73 and it has a 4sp. My first gear ratio in trans is 2.88 which is 10.74 with the 3.73.

REELAV8R

Probe SRS pistons? http://www.summitracing.com/parts/pb...make/chevrolet
With these I believe your compression height is .040" with .015 felpro, if I did the math right.
This link will help to compute it.
http://www.lunatipower.com/Tech/Pist...ionHeight.aspx

Flyinace3

My math was off you are correct quench is .040

glen242

FWIW, here is how I built mine. I decided upon a c.r. and built to that (+/- c.r. of 10.5) so I could run 89 octane pump gas.

TF aluminum heads 64cc.
-12 cc dish pistons
'0' deck block
0.041 head gaskets for 0.041 quench
static c.r. is 10.30. dynamic c.r. is a little over 8.0
cam is a CC XE-274 with an intake closing of 64*
timing is 35* all in at 2700 rpm
vacuum advance can is per Lars' recommendation to give total advance of 51*

I have been running this for about 5 years, without problems, using BP 89 octane fuel