340 vs 402. Help me decide what to build
02-13-2019, 01:09 PM
#23
Restricted User
Clutch and gear will give noticeable performance increases regardless of your engine setup. Seems like a no-brainer that they be your first choice for upgrades.
02-13-2019, 01:11 PM
#24
02-13-2019, 01:28 PM
#25
10 Second Club
iTrader: (8)
A light weight fly wheel on a ls7 clutch is still very heavy. The spec and qtr master i pointed you towards will weigh about 17-19 lb complete with a much reduced moi. That's what you want in a road course type car.
stick a msd intake on it with a 102 or 105 tb and see what it does. It should pick up 30-40whp and run to the higher rpm much easier.
No doubt changing the gear, clutch and intake is gonna lead to huge acceleration gains. You're looking at dropping 30lb or so off the crank with the clutch/fly set up. That alone is a pretty big change.
stick a msd intake on it with a 102 or 105 tb and see what it does. It should pick up 30-40whp and run to the higher rpm much easier.
No doubt changing the gear, clutch and intake is gonna lead to huge acceleration gains. You're looking at dropping 30lb or so off the crank with the clutch/fly set up. That alone is a pretty big change.
02-13-2019, 02:49 PM
#26
Cam change at this point is only going to pick up 20-30HP at most. The intake change will net you that.
And then the flywheel will net even more.
And then the gear will help it accelerate harder while in gear.
All positive things.
I would also look at CNC porting your current heads. That will net around 40HP. And it's throughout the range.
Moving to a 400cid engine adds a lot of cost. It includes all the above costs + the shortblock costs. And a Gen IV shortblock is going to be $5K from almost anywhere. And that extra $5K is going to net you probably 50-60HP over what heads/intake will net you (which will be about 60HP). Plus you have to swap out a lot of pieces like your valley cover, timing chain, etc. Nickle and dime you to death. So, it's not a great ROI.
If you do go with 400+cid, I would look at the LS3 heads and a 416... but to get 550+ out of it, you're going to have to drop some coin.
And then the flywheel will net even more.
And then the gear will help it accelerate harder while in gear.
All positive things.
I would also look at CNC porting your current heads. That will net around 40HP. And it's throughout the range.
Moving to a 400cid engine adds a lot of cost. It includes all the above costs + the shortblock costs. And a Gen IV shortblock is going to be $5K from almost anywhere. And that extra $5K is going to net you probably 50-60HP over what heads/intake will net you (which will be about 60HP). Plus you have to swap out a lot of pieces like your valley cover, timing chain, etc. Nickle and dime you to death. So, it's not a great ROI.
If you do go with 400+cid, I would look at the LS3 heads and a 416... but to get 550+ out of it, you're going to have to drop some coin.
02-13-2019, 03:15 PM
#27
A light weight fly wheel on a ls7 clutch is still very heavy. The spec and qtr master i pointed you towards will weigh about 17-19 lb complete with a much reduced moi. That's what you want in a road course type car.
stick a msd intake on it with a 102 or 105 tb and see what it does. It should pick up 30-40whp and run to the higher rpm much easier.
No doubt changing the gear, clutch and intake is gonna lead to huge acceleration gains. You're looking at dropping 30lb or so off the crank with the clutch/fly set up. That alone is a pretty big change.
stick a msd intake on it with a 102 or 105 tb and see what it does. It should pick up 30-40whp and run to the higher rpm much easier.
No doubt changing the gear, clutch and intake is gonna lead to huge acceleration gains. You're looking at dropping 30lb or so off the crank with the clutch/fly set up. That alone is a pretty big change.
02-13-2019, 03:53 PM
#29
Cam change at this point is only going to pick up 20-30HP at most. The intake change will net you that.
And then the flywheel will net even more.
And then the gear will help it accelerate harder while in gear.
All positive things.
I would also look at CNC porting your current heads. That will net around 40HP. And it's throughout the range.
Moving to a 400cid engine adds a lot of cost. It includes all the above costs + the shortblock costs. And a Gen IV shortblock is going to be $5K from almost anywhere. And that extra $5K is going to net you probably 50-60HP over what heads/intake will net you (which will be about 60HP). Plus you have to swap out a lot of pieces like your valley cover, timing chain, etc. Nickle and dime you to death. So, it's not a great ROI.
If you do go with 400+cid, I would look at the LS3 heads and a 416... but to get 550+ out of it, you're going to have to drop some coin.
And then the flywheel will net even more.
And then the gear will help it accelerate harder while in gear.
All positive things.
I would also look at CNC porting your current heads. That will net around 40HP. And it's throughout the range.
Moving to a 400cid engine adds a lot of cost. It includes all the above costs + the shortblock costs. And a Gen IV shortblock is going to be $5K from almost anywhere. And that extra $5K is going to net you probably 50-60HP over what heads/intake will net you (which will be about 60HP). Plus you have to swap out a lot of pieces like your valley cover, timing chain, etc. Nickle and dime you to death. So, it's not a great ROI.
If you do go with 400+cid, I would look at the LS3 heads and a 416... but to get 550+ out of it, you're going to have to drop some coin.
02-13-2019, 03:54 PM
#30
02-14-2019, 04:18 PM
#32
10 Second Club
iTrader: (8)
Ok....there is no magic head bullet to this ****. You put ls3 heads on it and you probably want to go solid roller and spin it to 8500 or so to make use of them. It's all about the combo. Right now your combo is fighting itself.
I use my own combo as a example which isn't my combo at all.....it's gm's combo. I made almost 70 more whp than you with a bolt on ls6. Heads is not your issue at this point.
I use my own combo as a example which isn't my combo at all.....it's gm's combo. I made almost 70 more whp than you with a bolt on ls6. Heads is not your issue at this point.
02-14-2019, 04:38 PM
#33
Ok....there is no magic head bullet to this ****. You put ls3 heads on it and you probably want to go solid roller and spin it to 8500 or so to make use of them. It's all about the combo. Right now your combo is fighting itself.
I use my own combo as a example which isn't my combo at all.....it's gm's combo. I made almost 70 more whp than you with a bolt on ls6. Heads is not your issue at this point.
I use my own combo as a example which isn't my combo at all.....it's gm's combo. I made almost 70 more whp than you with a bolt on ls6. Heads is not your issue at this point.
02-14-2019, 05:35 PM
#34
10 Second Club
iTrader: (8)
Cool....yea use this info to figure that thing out. I think your engine is cool af but something is a little off there imo. It should easily be making the power my bolt on ls6 does or more. I do have a ewp and i did bypass the power steering for that number but you should have no issues overcoming that with more compression and a cam.
Fixing those immediate issues is gonna be a large difference.
Fixing those immediate issues is gonna be a large difference.
02-21-2019, 10:49 AM
#36
10 Second Club
iTrader: (8)
Nice....you're gonna love it. Car will come off the corner so much better. Throttle response will be instant and make rev matching a breeze. It will also shift way better at high rpm.
you may need some tuning to make it drive nice. I turned off the throttle cracker in my tune and that helped a ton....that feature sucks with a stock clutch.
You'll also want to make a pedal stop. The throw of these style clutches are much shorter.
you may need some tuning to make it drive nice. I turned off the throttle cracker in my tune and that helped a ton....that feature sucks with a stock clutch.
You'll also want to make a pedal stop. The throw of these style clutches are much shorter.
02-21-2019, 11:03 AM
#37
Nice....you're gonna love it. Car will come off the corner so much better. Throttle response will be instant and make rev matching a breeze. It will also shift way better at high rpm.
you may need some tuning to make it drive nice. I turned off the throttle cracker in my tune and that helped a ton....that feature sucks with a stock clutch.
You'll also want to make a pedal stop. The throw of these style clutches are much shorter.
you may need some tuning to make it drive nice. I turned off the throttle cracker in my tune and that helped a ton....that feature sucks with a stock clutch.
You'll also want to make a pedal stop. The throw of these style clutches are much shorter.
I'll be looking to add a torque arm and or rear gear next depending on how the tires react to the new found acceleration and tune.
Last edited by Bearden4242; 02-21-2019 at 11:08 AM.