Compression ratio goals
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Compression ratio goals
I'm shootin' for a 10:1 with the following combo
-383-maching my existing block and installing forged internals
-74219 cam
-AFR 190's cnc'ed by TPIS-which I believe are 54cc
although I haven't plugged in my actual numbers to get my cr, I'm thinkin that with flat top pistons a stroker and the 54cc heads will make way too much compression
.
My question....Am I better off doing some bowl work to increase the cc or buy dished pistons....all in an effort to get close to my 10;1 cr.
Thanks,
Chuck
-383-maching my existing block and installing forged internals
-74219 cam
-AFR 190's cnc'ed by TPIS-which I believe are 54cc
although I haven't plugged in my actual numbers to get my cr, I'm thinkin that with flat top pistons a stroker and the 54cc heads will make way too much compression
.
My question....Am I better off doing some bowl work to increase the cc or buy dished pistons....all in an effort to get close to my 10;1 cr.
Thanks,
Chuck
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
There are still some unknowns here. Are you building for quench? Zero decking? I used SRP -16cc inverted domes. These are still flat in the quench area to reap that benefit and nicely designed in the valve area to enhance swirl and etc. With zero deck and 56cc heads I have about 10.8:1 with a .039" gasket and ended up with a good .041" quench. I believe they have a -24cc version which would be about right for your goal if you're zero decking. Otherwise, you could probably get around 10:1 with the -16cc ones.
Drifting
Joined: Apr 2003
Posts: 1,379
Likes: 4
From: rome ny
Originally Posted by chucks88
I'm shootin' for a 10:1 with the following combo
-383-maching my existing block and installing forged internals
-74219 cam
-AFR 190's cnc'ed by TPIS-which I believe are 54cc
although I haven't plugged in my actual numbers to get my cr, I'm thinkin that with flat top pistons a stroker and the 54cc heads will make way too much compression
.
My question....Am I better off doing some bowl work to increase the cc or buy dished pistons....all in an effort to get close to my 10;1 cr.
Thanks,
Chuck
-383-maching my existing block and installing forged internals
-74219 cam
-AFR 190's cnc'ed by TPIS-which I believe are 54cc
although I haven't plugged in my actual numbers to get my cr, I'm thinkin that with flat top pistons a stroker and the 54cc heads will make way too much compression
.
My question....Am I better off doing some bowl work to increase the cc or buy dished pistons....all in an effort to get close to my 10;1 cr.
Thanks,
Chuck
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Chuck assuming a few things your compression with 54cc heads will be much more than 10:1...
I have to ask, if your going to the trouble of building a stroker, why would you only want 10:1 compression? There are many examples of cars on here 85vet, our 406s and 434s, Ralphs 406 and some others I am sure are out there running 11.5:1 with no problems on the street. 11:1 is a no-brainer that it would be perfectly fine with 93 pump gas in any situation you would dream up.
The bump from 10:1 to 11:1 would be a gain of ~3% - why give that up? Its not any harder to get 11:1 as it would be 10:1....just some food for thought before its set in stone...
With some calculations and careful CCing of your components and machine work, obtaing a desired CR is very safe and managable,,,it just requires some up front work.
I have to ask, if your going to the trouble of building a stroker, why would you only want 10:1 compression? There are many examples of cars on here 85vet, our 406s and 434s, Ralphs 406 and some others I am sure are out there running 11.5:1 with no problems on the street. 11:1 is a no-brainer that it would be perfectly fine with 93 pump gas in any situation you would dream up.
The bump from 10:1 to 11:1 would be a gain of ~3% - why give that up? Its not any harder to get 11:1 as it would be 10:1....just some food for thought before its set in stone...
With some calculations and careful CCing of your components and machine work, obtaing a desired CR is very safe and managable,,,it just requires some up front work.
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
Chuck, one small detail when you finally calc it up......those heads of yours are advertised at 54cc (like an LT1 or LT5 factory head is). I have the same set (actually 187cc runners), had them checked and the chambers came out to 56cc.
You might want to have your measured, to be absolutely sure.
You might want to have your measured, to be absolutely sure.
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Thanks for all your imput here boys. This is my first build, I thought I did my homework, but I think I need to stay after for extra credit.
At any rate, I was a the builders today, and I mentioned to him about goosing the CR closer to 11:1. He is familiar with what I hope to get out of the car, which is a weekend warrior and a trip to the track maybe 4-6 times a year and He feels that that was too high.
After all he is putting his name on the short block....I guess it's obvious to him that I am a newby to this.
MOS 90- I already have the AFR/TPIS heads. I picked them up used for $1200
HOT ROD 90- I've read that too. I was planning on throwing the heads on a flow bench as well as double checking the cc's. Infact we need to do this before we pick out what type of pistons to go with.
I'm sure your be hearing more from me.
Chuck
At any rate, I was a the builders today, and I mentioned to him about goosing the CR closer to 11:1. He is familiar with what I hope to get out of the car, which is a weekend warrior and a trip to the track maybe 4-6 times a year and He feels that that was too high.
After all he is putting his name on the short block....I guess it's obvious to him that I am a newby to this.
MOS 90- I already have the AFR/TPIS heads. I picked them up used for $1200
HOT ROD 90- I've read that too. I was planning on throwing the heads on a flow bench as well as double checking the cc's. Infact we need to do this before we pick out what type of pistons to go with.
I'm sure your be hearing more from me.
Chuck
