Timing Question
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
Thread Starter
Pro
Joined: Feb 2007
Posts: 548
Likes: 1
From: Victoria VA
I was wondering because I'm using these heads on my 77 build and was told by some that they will take more timing and others that they must use less. My setup is Heads- 1988 chevy corvette 58cc chambers
Valves- stainless steel 1.94 intake 1.50 exhaust
Springs-Comp. Cams- part# 986 1.43 o.d Dia. 132@1.75 seat load 293@1.25 open load 1.15 coil bind and 322 lbs. rate. Retainers- Comp.Cams- part# 740-16 super lock retainers 10deg. lock angle
Rockers- Comp. Cams- part# 1417-16 magnum rollers 1.52 ratio with 3/8 rocker stud.
WORK Complete valve job, bronze guides, cut for PC seals, machine spring seat ,drill and helicoil bolt holes surface. pressure test, and shim springs.
I also have 96 corvette 2 1/2" manifolds a Edelbrock Performer RPM intake, Holley 650 double pumper dual feed w/ mech secondaries, TH 350 w B&M shift Kit, 3.70 rear I have the timing set at initial 16 degrees, mechanical 36 degrees in at 2500rpm and total 52 all in at 2800 rpms . Like I said I was told that 32-34 total mech should be the highest. I have not had a chance to take it out for a ride due to bad weather.
Valves- stainless steel 1.94 intake 1.50 exhaust
Springs-Comp. Cams- part# 986 1.43 o.d Dia. 132@1.75 seat load 293@1.25 open load 1.15 coil bind and 322 lbs. rate. Retainers- Comp.Cams- part# 740-16 super lock retainers 10deg. lock angle
Rockers- Comp. Cams- part# 1417-16 magnum rollers 1.52 ratio with 3/8 rocker stud.
WORK Complete valve job, bronze guides, cut for PC seals, machine spring seat ,drill and helicoil bolt holes surface. pressure test, and shim springs.
I also have 96 corvette 2 1/2" manifolds a Edelbrock Performer RPM intake, Holley 650 double pumper dual feed w/ mech secondaries, TH 350 w B&M shift Kit, 3.70 rear I have the timing set at initial 16 degrees, mechanical 36 degrees in at 2500rpm and total 52 all in at 2800 rpms . Like I said I was told that 32-34 total mech should be the highest. I have not had a chance to take it out for a ride due to bad weather.
Race Director
Joined: Sep 2003
Posts: 16,838
Likes: 341
From: Database Error Indiana
You will have to figure out what it needs. No real answer to that question. A long duration cam will bleed off cylinder pressure and the motor will like a lot of advance. Stock cam and 10.5 : 1 compression, not so much. Use premium gas and drive it. Start lower and advance it till it pings, then back it off 2*, is one old fashioned method. The motor I just took out of my Nova would lose ET with any more than 34* total. When I had a C3, I used a long duration cam and not so much compression and it would run great with 50* total. Trial and error, just do not error too much because spark knock can hurt a motor pretty fast.
Thread Starter
Pro
Joined: Feb 2007
Posts: 548
Likes: 1
From: Victoria VA
Sorry I did not say what cam I have it is the Comp 270H magnum cam I know I need to just drive it but the weather will be bad here for the next several days and after what I was told I just was wondering.
