Need quick help on LS7 430ci cam selection
Thread Starter
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
Need quick help on LS7 430ci cam selection My friend has a Corvette that he's buying a rebuilt LS7 motor. It was rebuilt for a boost application, then the prior owner decided to go another direction. This is what I know:
new LS7 block , 4.135 bore, 430ci
Callies Magnum crank
Oliver Billet rods
Mahle 930221635 flat top pistons, 2.5cc valve reliefs
Total Seal custom stainless top and Napier 2nd rings
Clevite H bearings
OEM LS7 heads done at Mast with ProFlow intake valves with lightly ported to match the valves, new valve guides and stainless valves, 65cc
head gasket .070 (yeah, I double-checked, not sure why this is here)
Align honed
Honed with plate
deck cylinders
set all bearing clearances for performance
balance and blueprint complete assembly
new cam
new ls7 lifters
new ctsv oil pump
LSXR intake
1 3/4" long tube headers
He seems to have narrowed down the cam selection to the following options, which are the shop recommendations for what they've used for many miles on LS7's without lifter failures. Main goal is reliability, no detonation issues, but he wants to do One Lap of America next year, so 5000 street miles pulling a small trailer (tires and tools) needs to be able to highway cruise pulling a trailer. Can't wait for a custom because it's tying up a lift at the shop. He's only going to rev it to 6500.
227/235 .614/.622 115+4 (he was going to pick this when he thought the motor was going to be 9.3 compression)
231/239 .617/.624 118+4
231/239 .617/.624 115+4
Any guidance for him on the cam selection to get him off the lift relatively quickly?
new LS7 block , 4.135 bore, 430ci
Callies Magnum crank
Oliver Billet rods
Mahle 930221635 flat top pistons, 2.5cc valve reliefs
Total Seal custom stainless top and Napier 2nd rings
Clevite H bearings
OEM LS7 heads done at Mast with ProFlow intake valves with lightly ported to match the valves, new valve guides and stainless valves, 65cc
head gasket .070 (yeah, I double-checked, not sure why this is here)
Align honed
Honed with plate
deck cylinders
set all bearing clearances for performance
balance and blueprint complete assembly
new cam
new ls7 lifters
new ctsv oil pump
LSXR intake
1 3/4" long tube headers
He seems to have narrowed down the cam selection to the following options, which are the shop recommendations for what they've used for many miles on LS7's without lifter failures. Main goal is reliability, no detonation issues, but he wants to do One Lap of America next year, so 5000 street miles pulling a small trailer (tires and tools) needs to be able to highway cruise pulling a trailer. Can't wait for a custom because it's tying up a lift at the shop. He's only going to rev it to 6500.
227/235 .614/.622 115+4 (he was going to pick this when he thought the motor was going to be 9.3 compression)
231/239 .617/.624 118+4
231/239 .617/.624 115+4
Any guidance for him on the cam selection to get him off the lift relatively quickly?
Last edited by JimMueller; Aug 19, 2019 at 07:40 PM. Reason: Title typo
TECH Addict
Joined: Sep 2010
Posts: 2,898
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It is a waste of of a 427 with only those cam specifications.
My recommendation will give you great driving manners once tuned and it will pull well everywhere even from low down in the rpm range.
236/248 115 LSA +3
With 12 degrees of overlap, this will have a nice muscle car idle, drive almost like stock and will pull ok up top too and will also be a pleasure to drive on long distances.
This would be the smallest camshaft I would use for what you are wanting to do.
My recommendation will give you great driving manners once tuned and it will pull well everywhere even from low down in the rpm range.
236/248 115 LSA +3
With 12 degrees of overlap, this will have a nice muscle car idle, drive almost like stock and will pull ok up top too and will also be a pleasure to drive on long distances.
This would be the smallest camshaft I would use for what you are wanting to do.
Banned
Joined: Jan 2019
Posts: 1,747
Likes: 100
Key words...no time. I'd just call ∆ and ask which one would work best for the application. 5min call then order, may have something on the shelf just for your friend. Win win.
Don't forget Lil John turbo specialist. ..... ....on the shelf maybe...but more than likely though
Don't forget Lil John turbo specialist. ..... ....on the shelf maybe...but more than likely though
Last edited by Smokey B; Aug 15, 2019 at 09:29 PM.
Hi Jim, Here are my thoughts:
With the engine exactly as configured below, stated goals, and especially no intention to rev past 6500, I'm coming up with 234/242-117+4. it does not have the traditional split, but he won't need it due to RPM goals. Would favor a bit more grunt in the midrange.
One concern i have is the head gasket. That much quench, I'm concerned will lead to inability to run better timing due to being a bit more sensitive to detonation. If you get to convince him to drop that HG to .044 range and get quench under control, that would bring him up to 12.5 compression, and obviously that's pushing it. Problem is, I would not want to push dynamic compression more than about 8.4 with that head gasket, which will cost a bit in terms of throttle response. So that 231/239-115+4 cam would likely be a KR-ing SOB. Same with that 227 spec.
The 231/239-118+4 spec isn't bad actually. It would drive very tame, have very good intake vacuum, but I think would be just a bit lacking on midrange torque, where the 234/242-117+4 I think will feel a bit stronger and should still be pretty tame to drive. As to the rest of the valve train, I would run PSI 1511 springs and run the lift to around 0.625 on the intake, which would be nice and light and help restore that throttle response and snappiness, making up for the dynamic compression being a bit low. As to pushrods, run 3/8", and I'm assuming stock rockers as well. Make sure to install lash caps ont he valves to avoid mushrooming the titanium intake valves. I recommend caps on all 16 to keep the geometry equal on both intake and exhaust on a LS7 set up.
Hope that all helps your friend.
With the engine exactly as configured below, stated goals, and especially no intention to rev past 6500, I'm coming up with 234/242-117+4. it does not have the traditional split, but he won't need it due to RPM goals. Would favor a bit more grunt in the midrange.
One concern i have is the head gasket. That much quench, I'm concerned will lead to inability to run better timing due to being a bit more sensitive to detonation. If you get to convince him to drop that HG to .044 range and get quench under control, that would bring him up to 12.5 compression, and obviously that's pushing it. Problem is, I would not want to push dynamic compression more than about 8.4 with that head gasket, which will cost a bit in terms of throttle response. So that 231/239-115+4 cam would likely be a KR-ing SOB. Same with that 227 spec.
The 231/239-118+4 spec isn't bad actually. It would drive very tame, have very good intake vacuum, but I think would be just a bit lacking on midrange torque, where the 234/242-117+4 I think will feel a bit stronger and should still be pretty tame to drive. As to the rest of the valve train, I would run PSI 1511 springs and run the lift to around 0.625 on the intake, which would be nice and light and help restore that throttle response and snappiness, making up for the dynamic compression being a bit low. As to pushrods, run 3/8", and I'm assuming stock rockers as well. Make sure to install lash caps ont he valves to avoid mushrooming the titanium intake valves. I recommend caps on all 16 to keep the geometry equal on both intake and exhaust on a LS7 set up.
Hope that all helps your friend.
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if he is going to drive around usa he may not be able to pick his gas - sometimes 91 or sometimes 93 is you max octane availble. Also he will be towing something. Keep compression less than 11.5 to 1.
Last edited by Double06; Aug 17, 2019 at 12:37 PM. Reason: adding stuff
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Verdad Gallardo Thread Starter
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
He says he changed his mind and ordered Wiseco pistons, in case he wants to use a small shot of nitrous. He's trying to get the Mahle pistons returned. Sticking with the 227/235 .614/.622 115+4. He's been provided a dyno graph of a stock C6Z (LS7) making 515/486 (SAE smoothing 5) on a Dynojet with that cam, he's hoping to be a little higher than that number. I've seen the graph it does have nice curve...450rwtq by 3000RPM, 486rwtq at 5100, 515rwp peak HP at 6100RPM. The HP doesn't carry too well past peakm but the long tube headers and LSXR will help that. I can understand that he wants to go with a cam that has known behavior, it's just that he's not quite comparing apples to apples. Don't know what to say, it's his money.
The heads don't have the Ti valves, and his math says DCR 8.8, SCR 10.8 with that cam, I don't have all the numbers to verify.
So his .050 VEs for the 227/235 115+4:
IVO 2.5
IVC 44.5
EVO 56.5
EVC -1.5
Jacob's suggestion, 234/242-117+4:
IVO 4
IVC 50
EVO 62
EVC 0
Overlap: 4*
Overlap Bias favors exhaust
Bortous suggestion #1, 236/248 115 LSA +3:
IVO 6
IVC 50
EVO 62
EVC 6
overlap 12*
No Overlap bias
Bortous suggestion #2, 234/246 116 LSA +3.
IVO 4
IVC 50
EVO 62
EVC 4
overlap 8*
No overlap bias
Wow, the recommendations have uncannily similar VEs
The heads don't have the Ti valves, and his math says DCR 8.8, SCR 10.8 with that cam, I don't have all the numbers to verify.
So his .050 VEs for the 227/235 115+4:
IVO 2.5
IVC 44.5
EVO 56.5
EVC -1.5
Jacob's suggestion, 234/242-117+4:
IVO 4
IVC 50
EVO 62
EVC 0
Overlap: 4*
Overlap Bias favors exhaust
Bortous suggestion #1, 236/248 115 LSA +3:
IVO 6
IVC 50
EVO 62
EVC 6
overlap 12*
No Overlap bias
Bortous suggestion #2, 234/246 116 LSA +3.
IVO 4
IVC 50
EVO 62
EVC 4
overlap 8*
No overlap bias
Wow, the recommendations have uncannily similar VEs
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
He says he changed his mind and ordered Wiseco pistons, in case he wants to use a small shot of nitrous. He's trying to get the Mahle pistons returned. Sticking with the 227/235 .614/.622 115+4. He's been provided a dyno graph of a stock C6Z (LS7) making 515/486 (SAE smoothing 5) on a Dynojet with that cam, he's hoping to be a little higher than that number. I've seen the graph it does have nice curve...450rwtq by 3000RPM, 486rwtq at 5100, 515rwp peak HP at 6100RPM. The HP doesn't carry too well past peakm but the long tube headers and LSXR will help that. I can understand that he wants to go with a cam that has known behavior, it's just that he's not quite comparing apples to apples. Don't know what to say, it's his money.
The heads don't have the Ti valves, and his math says DCR 8.8, SCR 10.8 with that cam, I don't have all the numbers to verify.
So his .050 VEs for the 227/235 115+4:
IVO 2.5
IVC 44.5
EVO 56.5
EVC -1.5
Jacob's suggestion, 234/242-117+4:
IVO 4
IVC 50
EVO 62
EVC 0
Overlap: 4*
Overlap Bias favors exhaust
Bortous suggestion #1, 236/248 115 LSA +3:
IVO 6
IVC 50
EVO 62
EVC 6
overlap 12*
No Overlap bias
Bortous suggestion #2, 234/246 116 LSA +3.
IVO 4
IVC 50
EVO 62
EVC 4
overlap 8*
No overlap bias
Wow, the recommendations have uncannily similar VEs
The heads don't have the Ti valves, and his math says DCR 8.8, SCR 10.8 with that cam, I don't have all the numbers to verify.
So his .050 VEs for the 227/235 115+4:
IVO 2.5
IVC 44.5
EVO 56.5
EVC -1.5
Jacob's suggestion, 234/242-117+4:
IVO 4
IVC 50
EVO 62
EVC 0
Overlap: 4*
Overlap Bias favors exhaust
Bortous suggestion #1, 236/248 115 LSA +3:
IVO 6
IVC 50
EVO 62
EVC 6
overlap 12*
No Overlap bias
Bortous suggestion #2, 234/246 116 LSA +3.
IVO 4
IVC 50
EVO 62
EVC 4
overlap 8*
No overlap bias
Wow, the recommendations have uncannily similar VEs
Thread Starter
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
How do I correct that formula?
A 227 degree intake cam on a 430? I'm running a BTR stage 2(227/234) on a 346 and it's a fairly tame cam. I hit peak at about 6200 rpm on a 346. IMO that's too small. I think Jacobs cam would drive great on the street. I wouldn't go smaller that that 234 intake duration.
Last edited by wannafbody; Aug 21, 2019 at 11:04 PM.
Call Kip at Cammotion and you will be glad you did. The camshaft is one of the most important parts in a motor.... those ones you listed are tiny and a waste of time.
I had an LS7 with a 243/256 .650" lift cam and headers/stock intake manifold and it drove perfectly plus it was setup as a road race car (2800lb RX-7 chassis). Made only 520rwhp.... but did go low 10's@ 110mph 1/8th and 138mph in the 1/4 on 91 octane thru dual 3" Random Technology catalytic convertors...
I had an LS7 with a 243/256 .650" lift cam and headers/stock intake manifold and it drove perfectly plus it was setup as a road race car (2800lb RX-7 chassis). Made only 520rwhp.... but did go low 10's@ 110mph 1/8th and 138mph in the 1/4 on 91 octane thru dual 3" Random Technology catalytic convertors...
Thread Starter
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
Now he's back to using the Mahle's which will take 4-6 weeks, so he said F it and ordered a custom EPS 230/242 116+3 (284/296 advertised) .629/.604 cam also. He did talk about calling CamMotion, not sure what happened with that.
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Joined: Jan 2019
Posts: 1,747
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My friend/ Lil brother in real life and a tech forum user loves EPS. Helping him spec his 408 for a turbo setup for liberty 11 degree ls3 heads for his 94 Camaro. ...shooting for 800/800 with @ most 20 lbs of boost. Has everything except crank & heads. We're doing simple math 400/400 na add boost. Other 02 camaro is a 6.0 na higher compression EPS cam also helped spec it also besides camming. Never dealt with EPS but he's happy. Think he's been dealing with Jeff.
Even with turbo or supercharger my desire would be RPM. I’d want it to look like an NA curve just fatter everywhere. IMO that’s how you know it was sized properly for the power and cubic inches.
That's decent. it will still be quite tame to drive, but will work good with the compression. Did you ever get to talk with him about the HG and quench? If he ever ends up needing to run 91 octane, he's going to want to keep some boostane handy with that quench and 8.6 dynamic compression. But the cam should be a good midrange runner and help with the towing. It will peak early and fall off, but since he;s not revving past 6500 anyway, it should carry that far at least.
Staging Lane
Joined: Apr 2015
Posts: 94
Likes: 1
My friend/ Lil brother in real life and a tech forum user loves EPS. Helping him spec his 408 for a turbo setup for liberty 11 degree ls3 heads for his 94 Camaro. ...shooting for 800/800 with @ most 20 lbs of boost. Has everything except crank & heads. We're doing simple math 400/400 na add boost. Other 02 camaro is a 6.0 na higher compression EPS cam also helped spec it also besides camming. Never dealt with EPS but he's happy. Think he's been dealing with Jeff.
I have 3 cams 2 of which Geoff has speced for me and one is a thunder racing tr224 from like 08, That cam has been through basically 3 different motors for daily/street all I can say is I’m very happy with all around service and performance but that’s is just my opinionnot-a-sponsor.com
Last edited by KCS; Aug 22, 2019 at 08:05 AM. Reason: Non sponsor info removed
Thread Starter
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
That's decent. it will still be quite tame to drive, but will work good with the compression. Did you ever get to talk with him about the HG and quench? If he ever ends up needing to run 91 octane, he's going to want to keep some boostane handy with that quench and 8.6 dynamic compression. But the cam should be a good midrange runner and help with the towing. It will peak early and fall off, but since he;s not revving past 6500 anyway, it should carry that far at least.