Build Guidance Questions
Build Guidance Questions I have a Combination Motorsports LT1 cam from a few years ago.
Here are the cam specs:
Part # 07-000-8
Engine LT1/LT4
Grind # LT1 3442/3442 HR112+1
Serial # A 3262
Gross valve lift .569/.577
Duration at .006 283/289
Valve timing at .050:
INT OPEN 8 BTDC CLOSE 44 ABDC
EXH OPEN 55 BBDC CLOSE 3 ATDC
These specs are for cam installed at 108 intake centerline:
Duration at .050 233/239
Lobe lift .3560/.3610
Lobe Seperation 112.0
I have a very low mile replacement LT1 4-bolt main(8,000-10,000 miles).
Also have ported and larger valve GM LT1 heads with complete CC roller valvetrain
I'm not needing a 10.5 second car, 11.5-11.0 is target(FYI)
My ?'s are:
1) Where is this cams power gonna be? (6400-6800rpm)?
2) Am I gonna be ok with ARP bolted stock rods and pistons?
3) (If necessary to replace pistons and rods) Whats some advantages of a 6" rod package?
Thanks,
Darrell
Here are the cam specs:
Part # 07-000-8
Engine LT1/LT4
Grind # LT1 3442/3442 HR112+1
Serial # A 3262
Gross valve lift .569/.577
Duration at .006 283/289
Valve timing at .050:
INT OPEN 8 BTDC CLOSE 44 ABDC
EXH OPEN 55 BBDC CLOSE 3 ATDC
These specs are for cam installed at 108 intake centerline:
Duration at .050 233/239
Lobe lift .3560/.3610
Lobe Seperation 112.0
I have a very low mile replacement LT1 4-bolt main(8,000-10,000 miles).
Also have ported and larger valve GM LT1 heads with complete CC roller valvetrain
I'm not needing a 10.5 second car, 11.5-11.0 is target(FYI)
My ?'s are:
1) Where is this cams power gonna be? (6400-6800rpm)?
2) Am I gonna be ok with ARP bolted stock rods and pistons?
3) (If necessary to replace pistons and rods) Whats some advantages of a 6" rod package?
Thanks,
Darrell
That cam will need all the rpm the pcm can give it as long as the heads are decent.
6.0" rods let you run a lighter piston which makes life easier on the rotating assembly, all the other "reasons" people give beyond that are pretty much just bench racing theory not practical and useful.
The guys at Combination Motorsports were good guys but nothing they did really stood out performance wise and everything they offered is grossly outdated, I suggest you consider stepping up to more current setups.
When CM was in it's prime the fastest heads/cam/spray Impala was slower than the fastest heads/cam cars are today, the difference is that drastic.
6.0" rods let you run a lighter piston which makes life easier on the rotating assembly, all the other "reasons" people give beyond that are pretty much just bench racing theory not practical and useful.
The guys at Combination Motorsports were good guys but nothing they did really stood out performance wise and everything they offered is grossly outdated, I suggest you consider stepping up to more current setups.
When CM was in it's prime the fastest heads/cam/spray Impala was slower than the fastest heads/cam cars are today, the difference is that drastic.
So, a spec'd custom cam with my mildly ported larger valve heads, may be capable of getting mid 11's, under 6800rpm, with my stock rods and pistons being still in a safe range.
I guess what I'm looking to do is get approx. 1.5 seconds out of a heads/cam package, preferably on arp bolted stock rods and pistons. This is for my well prepped 'bird which still don't have headers or custom tune. So I don't think I need a whole bunch more power to get my target. I was thinking this cam may be more than wanted rpm wise, thanks.
I guess what I'm looking to do is get approx. 1.5 seconds out of a heads/cam package, preferably on arp bolted stock rods and pistons. This is for my well prepped 'bird which still don't have headers or custom tune. So I don't think I need a whole bunch more power to get my target. I was thinking this cam may be more than wanted rpm wise, thanks.
https://ls1tech.com/forums/lt1-lt4-m...1-119-7-a.html
This car is more race prepped and mine more street, power everything, AC, ABS, driven 150miles each way to Great Lakes Dragaway, and home on one tank of gas. I run through full exhaust to the bumper mufflers and resonators
You use the same parts and low 11s should be easy in an f-body, your rowing ability should be the hardest part. With a 6 speed though I would really look at 4.10s.
This car is more race prepped and mine more street, power everything, AC, ABS, driven 150miles each way to Great Lakes Dragaway, and home on one tank of gas. I run through full exhaust to the bumper mufflers and resonators
You use the same parts and low 11s should be easy in an f-body, your rowing ability should be the hardest part. With a 6 speed though I would really look at 4.10s.
https://ls1tech.com/forums/lt1-lt4-m...1-119-7-a.html
This car is more race prepped and mine more street, power everything, AC, ABS, driven 150miles each way to Great Lakes Dragaway, and home on one tank of gas. I run through full exhaust to the bumper mufflers and resonators
You use the same parts and low 11s should be easy in an f-body, your rowing ability should be the hardest part. With a 6 speed though I would really look at 4.10s.
This car is more race prepped and mine more street, power everything, AC, ABS, driven 150miles each way to Great Lakes Dragaway, and home on one tank of gas. I run through full exhaust to the bumper mufflers and resonators
You use the same parts and low 11s should be easy in an f-body, your rowing ability should be the hardest part. With a 6 speed though I would really look at 4.10s.
