classic car - not interested in max power

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Jan 4, 2017 | 01:54 PM

dewchugr

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classic car - not interested in max power

The car -71 Cutlass convertible, currently doing a frame off restoration. I'm adding C6 brakes and probably 325 tires and 373 gears.

The motor - 5.3, 06 LH6, with the TBSS intake and 243 heads. I think about 140k on it. I have everything from the Rainier, keeping the AC. Transmission will most likely be a 4L80.

Goals, reliable, dependable and durable. I want the car to appear stock on the exterior for the most part. Bought the motor with a lifter that came apart, so I was planning to change the lifters and cam to get rid of the dod and go for 400-450 hp.

Now, my son gave me a VS GT45 69mm turbo so now I'm trying to figure out what to do. I want to be able to drive it across the country without worrying about it. I want it to be quick too, but that's secondary. I want dual exhaust and I don't want a shiny inter-cooler that stands out, black would work.

My questions are what should we try to limit the boost to? Do I get a stock/ls6 cam and let the turbo make up for it or get something better performing? What kind of power can I get with these goals? This is going to be a street car. Should I use the stock ECU or would something different be better.

Jan 4, 2017 | 02:17 PM

cajundragger

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4-450hp na is pushing it with a mostly stock 5.3 when you claim you want durability.

it's very hard for us to answer what you should do. Now, if you decide you want to go turbo, then we could help with that.

seems like you'd be best to slap it together and get on the road. IMO.

Jan 4, 2017 | 03:03 PM

dewchugr

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Launching!

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Quote:

Originally Posted by cajundragger

I think turbo is the way to go since I have it now. How much boost can we use with this turbo while keeping it reliable long term?

Jan 4, 2017 | 03:06 PM

JoeNova

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From: Ohio

The LH6 can take everything that GT45 can throw at it.

Jan 10, 2017 | 04:10 PM

Narxoleptic

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From: Northwest Arkansas

14.7 psi of boost should do you great... just buy the "Denmah kit" from VSRacing and that should include everything you need. Then take it to your tuner and tell them what you want. 500 hp shouldnt be too hard to get....

Jan 10, 2017 | 05:06 PM

callys

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From: Vista, CA

I've finished two A body ls swaps and one G body (grand national). All of them are "nice" cars that can be driven anywhere. Here are my thoughts:

Unless you heard the engine run or drove the former vehicle I would at least inspect the engine - I've blown up two LSes by not doing this
I would do everything possible to box your frame, even moreso than the factory convertible boxing - this will have the largest impact on the driveability, rattle-free nature of the finished car
C6 brakes and big wheels/tires are fairly high dollar items, have you considered an all aftermarket frame like the Schwartz? Its not as expensive as you think when you add everything up
By time you build an 8.5" 10 bolt or 12 bolt for that car it can be the same money as the 9" - the schwartz frame is setup to use that
There really is no point in dual exhaust with a turbo
3.73 gear ratio is too much and will make the car wild at low speed - read the sloppy mechanics page one of his cars picked up considerably when he reduced his gear from a 3.55 or 3.73 to a 3.15
You can Y a 3" or 3.5" downpipe into the dual exhaust - you wont need much muffler with that setup
You should do a stronger than stock valve spring to control the valves under boost no matter what
I disagree with most people here. I don't think spending $400 or more on a cam is worth it on the power level you are looking for.
You can hit more power than you want with 8-10 psi and skip the methanol injection and all the extra complication.
Please don't use a 4l60e
Both A bodies I've done were BOP cars - we had to cut and raise the tunnel considerably for the 4l80e
There is nothing wrong with a black intercooler

Jan 10, 2017 | 05:29 PM

Project GatTagO

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From: Little Austin

If there is budget for it, I strongly suggest using the Holley Dominator ECU. It will handle all your engine tuning for boost, 4L80e trans, and have built in boost control strategies, all in one ECU.

Andrew

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Feb 2, 2017 | 08:48 AM

dewchugr

Thread Starter

Launching!

Joined: Feb 2014

Posts: 206

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Quote:

Originally Posted by callys

I've finished two A body ls swaps and one G body (grand national). All of them are "nice" cars that can be driven anywhere. Here are my thoughts:

Unless you heard the engine run or drove the former vehicle I would at least inspect the engine - I've blown up two LSes by not doing this
I would do everything possible to box your frame, even moreso than the factory convertible boxing - this will have the largest impact on the driveability, rattle-free nature of the finished car
C6 brakes and big wheels/tires are fairly high dollar items, have you considered an all aftermarket frame like the Schwartz? Its not as expensive as you think when you add everything up
By time you build an 8.5" 10 bolt or 12 bolt for that car it can be the same money as the 9" - the schwartz frame is setup to use that
There really is no point in dual exhaust with a turbo
3.73 gear ratio is too much and will make the car wild at low speed - read the sloppy mechanics page one of his cars picked up considerably when he reduced his gear from a 3.55 or 3.73 to a 3.15
You can Y a 3" or 3.5" downpipe into the dual exhaust - you wont need much muffler with that setup
You should do a stronger than stock valve spring to control the valves under boost no matter what
I disagree with most people here. I don't think spending $400 or more on a cam is worth it on the power level you are looking for.
You can hit more power than you want with 8-10 psi and skip the methanol injection and all the extra complication.
Please don't use a 4l60e
Both A bodies I've done were BOP cars - we had to cut and raise the tunnel considerably for the 4l80e
There is nothing wrong with a black intercooler

WOW, thank for all of that information. We will be checking out the engine. When I got it it ran, but made noise, turns out one of the DOD lifters came apart in the middle. I have to replace the cam and other stuff to get rid of the DOD. The Schwartz frames are nice, but out of my budget.

I got the C6 calipers, brackets, pads, rotors with 10k on them for $250, rear f-body backing plates for $50 and front brackets for $0, so this is cheaper than any other option. I know the wheels won't be cheap, but some things can't be helped. I want bigger wheels anyway.

I can get everything for the rear end for around $700. I'm pretty sure I have someone that can help put it together. Going to check out that sloppy page when I'm done, thanks.

I'd get a t56, but that and some other things I'd like to do aren't happening due to the fact that I have to pay for body work and paint as well as rust repair. Definitely not a 4L60. I've read some that with the Holley mounts you can get away with minor tunnel mods. Have to research more tho.

I don't need dual exhaust, but I want to keep the look.

Thanks again for the information!