Questions on stroking and forged internals.

[LS7 427]

I currently have a TVS2300 that has the intake ported, LPE 69cc CNC heads with upgraded valve train, LPE GT-9 cam, L99 -LS3 conversion, RotFab CAI, Stainlessworks 1-7/8" headers and 3" exhaust. Not really related but for information purposes I also have an RPM Transmission 3.70 diff, DSS 1400 hp axles, Phadt diff bushings, subframe bushings, sway bars and inverted coilovers.

The car dyno's at 590rwhp and I am running a conservative 7lbs boost to preserve the stock bottom end, which leads me to my questions. I would like to stroke my motor and replace the rotating system with forged internals to be able to increase boost to10psi. My goal is to have a car who's application is about 60% track and 40% street.

My preference would be to stroke the 376ci. motor to 427ci. with ~10:1 compression.

Question #1

• Can I get 427ci. by leaving the bore stock and increasing piston stroke?

Question #2

• What would you recommend for crank, pistons, rings, etc?

Question #3

• I would like to get just slightly more aggressive with the cam, what could replace the GT-9 to accomplish this?

Question # Last

• Could I reuse the LPE 69cc heads or would I need the 73cc to have 10:1 compression?

Thanks, Bryan

[Notneb]

Bump

[jrpxxii]

Originally Posted by CAMROSS

I currently have a TVS2300 that has the intake ported, LPE 69cc CNC heads with upgraded valve train, LPE GT-9 cam, L99 -LS3 conversion, RotFab CAI, Stainlessworks 1-7/8" headers and 3" exhaust. Not really related but for information purposes I also have an RPM Transmission 3.70 diff, DSS 1400 hp axles, Phadt diff bushings, subframe bushings, sway bars and inverted coilovers.

The car dyno's at 590rwhp and I am running a conservative 7lbs boost to preserve the stock bottom end, which leads me to my questions. I would like to stroke my motor and replace the rotating system with forged internals to be able to increase boost to10psi. My goal is to have a car who's application is about 60% track and 40% street.

My preference would be to stroke the 376ci. motor to 427ci. with ~10:1 compression.

Question #1

• Can I get 427ci. by leaving the bore stock and increasing piston stroke?

Question #2

• What would you recommend for crank, pistons, rings, etc?

Question #3

• I would like to get just slightly more aggressive with the cam, what could replace the GT-9 to accomplish this?

Question # Last

• Could I reuse the LPE 69cc heads or would I need the 73cc to have 10:1 compression?

Thanks, Bryan

Sure you can, just take the motor you have now, jerk it out, replace with an LSX427 and build as you would like it.

[hot ss]

did you ask steve as well??

[NEGXXIS]

427 cubes on a LS3 based engine is not really recommended for boost, the piston is not as thick as a 416 or 418. But there are some people that have good luck with a boosted LS3 based 427. I am hoping that I will be one of the lucky ones since that is exactly what I am doing as we speak.
Good luck with you project which ever way you choose to go.

[LS7 427]

Originally Posted by hot ss

did you ask steve as well??

Yes, we've been discussing it at length. His shop will do the build, but he has challenged me to do my homework on 416 vs 427 before he takes my cash.

Originally Posted by EZ SPEED

427 cubes on a LS3 based engine is not really recommended for boost, the piston is not as thick as a 416 or 418. But there are some people that have good luck with a boosted LS3 based 427. I am hoping that I will be one of the lucky ones since that is exactly what I am doing as we speak.
Good luck with you project which ever way you choose to go.

Thanks for the info.

Bryan

[old motorhead]

I'd leave the cubes as is. Cubes aren't going to limit you. After you build a forged bottom, you can spin the TVS up to its practical limits anyway. About the only thing more cubes will give you is more power down low. I'm guessing with a forged bottom and 3" blower pulley, you'll have all you can handle. You'll keep a few more bucks in the bank and get a little better mpg too. You're about at the point where a little more costs a lot more. Yes, absolutely, you can push it. For me, it wouldn't be worth it. Guess you have to decide

If you are hell bent on stroking it, my vote would go for the 416. Those extra few cubes come at a price.

[Slim2SS]

Originally Posted by old motorhead

I'd leave the cubes as is. Cubes aren't going to limit you. After you build a forged bottom, you can spin the TVS up to its practical limits anyway. About the only thing more cubes will give you is more power down low. I'm guessing with a forged bottom and 3" blower pulley, you'll have all you can handle. You'll keep a few more bucks in the bank and get a little better mpg too. You're about at the point where a little more costs a lot more. Yes, absolutely, you can push it. For me, it wouldn't be worth it. Guess you have to decide

If you are hell bent on stroking it, my vote would go for the 416. Those extra few cubes come at a price.

X2

[Jason 98 TA]

We can select a piston to get compression where we need it so there should be no issue there. We do a lot of the 418s for Maggie customers and you should be able to support 900 flywheel hp with that blower. . Give us a call to discuss your combo, I bet we have a few short blocks in stock to get you going.

[Z_Rocks]

Originally Posted by old motorhead

I'd leave the cubes as is. Cubes aren't going to limit you. After you build a forged bottom, you can spin the TVS up to its practical limits anyway. About the only thing more cubes will give you is more power down low. I'm guessing with a forged bottom and 3" blower pulley, you'll have all you can handle. You'll keep a few more bucks in the bank and get a little better mpg too. You're about at the point where a little more costs a lot more. Yes, absolutely, you can push it. For me, it wouldn't be worth it. Guess you have to decide

If you are hell bent on stroking it, my vote would go for the 416. Those extra few cubes come at a price.

AS he says above. When your F/I use the S/C to get more air into the engine than cube would. That's what F/I does without the need of going bigger cube. The 2.0 liter Ecotec from GM and a turbo was able to produce 1000 HP from crate engine.
Keep your stock cube and spend that money on drive train and suspension and tranny, where you will need it. Again, with a good designed F/I engine, you can get a lot of power even from a small engine.
I saw a Honda S2000 putting out 700 RWHP in front of my own eyes with a single turbo.

[Notneb]

Slim2SS what kind of hp is your setup putting down?