piston dome volume on a stock 350

Lyn Smith · 10-22-2012, 01:06 PM

What would the piston dome volume number be on a stock .030 over 1977 350 chevy with stock 4 valve relief flat top pistons? just a ball park figure will work. thanks

Greg Hill · 10-22-2012, 02:23 PM

Lynn, do you mean the dish? If you do it's in the blueprint specifications on the NHRA site. I just looked and it's 9.92 cc's.

Lyn Smith · 10-22-2012, 04:33 PM

thanks Greg,but i think that is suppose to be a minus number on a dish piston.I came up with 12 to 1 on the plus number and 9.6 to 1 on the minus number.Im putting some 56 cc 305 heads on a flat top 4 valve relief 350 street motor.

Greg Hill · 10-22-2012, 07:11 PM

Quote:

Originally Posted by Lyn Smith

thanks Greg,but i think that is suppose to be a minus number on a dish piston.I came up with 12 to 1 on the plus number and 9.6 to 1 on the minus number.Im putting some 56 cc 305 heads on a flat top 4 valve relief 350 street motor.

I would use a thick head gasket if you want to run pump gas. How much deck will you have?

Mike Taylor 3601 · 10-22-2012, 08:03 PM

I calculated it 3 ways If you have regular cast pistons like federal mogul 436p the compression distance is .020 shorter than oem piston, the shorter ones will be 1.540 comp.distance. most hypertec. and forged will be 1.560 comp. distance.

Here's the 3 ways I figured.
Block not decked 9.025, w/-9.92cc dish/valve pocket,56cc head,.039 X4.100 head gasket,.045 deck clearance,which will be close to what you have w/9.025 deck and 1.540 comp dist.
will be 9.7-to 1

w/.025 deck clearance will be 10.15-to 1

w/.000 deck clearance will be 10.8-to 1
You probaly will have the same as one of these combinations depending on comp.distance of pistons,and deck height of block.

I would want it to be 9.7 or less for 93 pump gas,also is less likely to detonate if piston to head clearance is not over .040.

If you have'nt cc'ed head it may be 3-6 cc bigger than it is supposed to be.It takes
about .007-.008milling to remove 1 cc.
If it was me I would use 76cc heads w/zero deck and flat tops or use dish pistons w/305 heads
Mike Taylor 3601

Lyn Smith · 10-22-2012, 10:41 PM

Mike, thanks for doing the figuring.9.7 is what i came up with also.

BillK · 10-23-2012, 12:21 PM

Lyn,
You need to make sure of the piston you have. The true flat top 350 pistons like the 345NP Sealed Power are right around -5cc. The -9.92cc sounds like the 423NP piston with the slight dish and 4 valve reliefs.

Mike Taylor 3601 · 10-23-2012, 01:34 PM

I think you correct Bill K 350 dish in NHRA spec is- 9.92cc 423 piston would be that piston.

Mike Taylor 3601

10-22-2012, 01:06 PM	#1
Lyn Smith VIP Member Join Date: Dec 2001 Location: Pontiac,il. Posts: 1,126 Likes: 223 Liked 860 Times in 160 Posts	piston dome volume on a stock 350 What would the piston dome volume number be on a stock .030 over 1977 350 chevy with stock 4 valve relief flat top pistons? just a ball park figure will work. thanks

10-22-2012, 02:23 PM	#2
Greg Hill VIP Member Join Date: May 2006 Location: Louisville , KY Posts: 1,994 Likes: 63 Liked 270 Times in 68 Posts	Re: piston dome volume on a stock 350 Lynn, do you mean the dish? If you do it's in the blueprint specifications on the NHRA site. I just looked and it's 9.92 cc's. __________________ Greg Hill 4171 STK

10-22-2012, 04:33 PM	#3
Lyn Smith VIP Member Join Date: Dec 2001 Location: Pontiac,il. Posts: 1,126 Likes: 223 Liked 860 Times in 160 Posts	Re: piston dome volume on a stock 350 thanks Greg,but i think that is suppose to be a minus number on a dish piston.I came up with 12 to 1 on the plus number and 9.6 to 1 on the minus number.Im putting some 56 cc 305 heads on a flat top 4 valve relief 350 street motor.

10-22-2012, 08:03 PM	#5
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,303 Likes: 198 Liked 116 Times in 48 Posts	Re: piston dome volume on a stock 350 I calculated it 3 ways If you have regular cast pistons like federal mogul 436p the compression distance is .020 shorter than oem piston, the shorter ones will be 1.540 comp.distance. most hypertec. and forged will be 1.560 comp. distance. Here's the 3 ways I figured. Block not decked 9.025, w/-9.92cc dish/valve pocket,56cc head,.039 X4.100 head gasket,.045 deck clearance,which will be close to what you have w/9.025 deck and 1.540 comp dist. will be 9.7-to 1 w/.025 deck clearance will be 10.15-to 1 w/.000 deck clearance will be 10.8-to 1 You probaly will have the same as one of these combinations depending on comp.distance of pistons,and deck height of block. I would want it to be 9.7 or less for 93 pump gas,also is less likely to detonate if piston to head clearance is not over .040. If you have'nt cc'ed head it may be 3-6 cc bigger than it is supposed to be.It takes about .007-.008milling to remove 1 cc. If it was me I would use 76cc heads w/zero deck and flat tops or use dish pistons w/305 heads Mike Taylor 3601

10-22-2012, 10:41 PM	#6
Lyn Smith VIP Member Join Date: Dec 2001 Location: Pontiac,il. Posts: 1,126 Likes: 223 Liked 860 Times in 160 Posts	Re: piston dome volume on a stock 350 Mike, thanks for doing the figuring.9.7 is what i came up with also.

10-23-2012, 12:21 PM	#7
BillK Member Join Date: Nov 2005 Location: Waldorf Md Posts: 222 Likes: 10 Liked 26 Times in 15 Posts	Re: piston dome volume on a stock 350 Lyn, You need to make sure of the piston you have. The true flat top 350 pistons like the 345NP Sealed Power are right around -5cc. The -9.92cc sounds like the 423NP piston with the slight dish and 4 valve reliefs. __________________ Bill Koustenis

10-23-2012, 01:34 PM	#8
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,303 Likes: 198 Liked 116 Times in 48 Posts	Re: piston dome volume on a stock 350 I think you correct Bill K 350 dish in NHRA spec is- 9.92cc 423 piston would be that piston. Mike Taylor 3601