[1963SS]

Check out the Torquehead 24x conversion. It completely does away with the Opti and uses a LS computer that's pre-wired for your harness. No 7200 RPM limit. Why do you want to go more than 7200? Thinking of running NASCAR?

Just get a Callies Magnum XL crank, Mahle Powerpak pistons and some Lunati rods. The pistons only weigh about 450 grams, the crank is about 10 pounds lighter than stock and will handle any power you want. Throw on a good McLeod Street Twin clutch with n aluminum flywheel and the engine will rev like a dentist's drill.

 

[1963SS]

Where to start? I have two LT4 engines in two separate Impala SS cars. One is a six-speed and one is an automatic. The automatic car has a pretty nasty build but is perfectly driveable. We've taken it on a 5000 mile road trip and the Hot Rod Power Tour that was about 3500.

Don't waste your time or money with the Edelbrock Air Gap. There has never been any proven gains with it over the stock LT1/LT4 manifolds. The ported stock intake will support a bunch of horsepower. The TPIS Miniram may make a bit more power but the last guy that tried it for a performance said he had problems with fitment and required a lot of porting to get it to match up. There were also problems with porosity in the casting. H did use it but said he wouldn't do it again. Two of the best porting folk for these engines are Lloyd Elliot at Elliot Portworks and Advanced Induction.

http://elliottsportworks.com/home/?page_id=55

http://www.advancedinduction.com/LTX/AiLTxHeadsCamKits.php

Both of these are about the best for our engines and Lloyd will custom spec a cam just for your application and set your heads up with the proper springs while he has it. The LE3 heads have bigger valves also. 2.05/1.6". Both guys will do the heads/cam that will necessitate a full cage. You probably don't want that for the street. Lloyd is much, much easier to get hold of and he will talk with you about your build as long as you like. Phone calls are really cheap. When he did his LE3 porting on my LT4 heads I got out my trusty burette and measure the ports at exactly 227cc's. That will lower your torque a bit but will scream up high. With the light weight of the Vette you'll not need any more torque than that.

I used the AFR 1039 on my big build. They have great flow numbers and are known to make big power on the dyno and at the track. 2.08 valves and all. Check them out at the following link. They're pricey but well worth it. Tony Mamo, the #1 head designer for AFR did a little hand massaging on mine and they flow just a bit better. I told him I wouldn't tell how much.
http://www.airflowresearch.com/195cc-sbc-lt4-competition-cylinder-head/

You will want to use guide plates and NSA rocker arms for a big lift cam. The self-aligning will cause problems that cost a bunch to fix.

If you need the 227 heads AFR solution is monster 2.100 valves in their #1126 heads. They flow way, way up there.

https://www.jegs.com/p/AFR-Airflow-Research/AFR-Small-Block-Chevy-227cc-LT4-Eliminator-Race-Aluminum-Cylinder-Heads/2832298/10002/-1

These engines love compression in the 11.5-12.2 compression. You'll have no knock counts and the tune will be easy. I've used Lunati, Callies Dragonslayer and Eagle cranks with no issues at all. I'm currently running the Dragonslayer crank, Lunati rods and Mahle Powerpak pistons and rings.

Both of mine are 383's and the clearancing wasn't bad at all. Any good machine shop will know exactly what to do. Core shift has never been an issue for me with the LT engines. Just a few notches on the bottom of the bores and a touch of grinding on the pan gasket surface. With a Vette I'd probably stick with a 350/355 and use the quicker revving as a tool. You won't need the added torque that a 383 will give you..........unless you really want it.

I went with a 4.56 gear in a 4300 pound Impala but I'm certain that a 4.10 would be all that's needed in your D-44 rear. This is also a good time to get an Eaton 400# posi unit. Use the money you were going to spend on the Air Gap and buy the posi and gears.

As far as the clutch, it is a good idea to do away with the dual mass. I personally like the McLeod twin disc but I have a very heavy car. Your Vette sould be great with the Street Extreme Part number 75218. The horsepower rating is "only" 500 HP but in a light Vette it should do fine at higher HP numbers. I used it on the 550 HP Impala for three years without a problem. Take-up is great and there's no shudder at all. It is a bit noisier than the dual mass but that's to be expected.

You're going to be limited to about 7200 RPM by your cars electronics. That's the bad news. The good news is that it's plenty high enough.

I'm using a Comp Cam that has a 242/248 duration @.050 with .584/.579 lift on a 113 degree. The 113 makes life a bit easier on the tuner and has just a plain, nasty sound. I start the shift at 6500 and it'll see about 6800 before it's done.

I used a Magnaflow X-pipe muffler on my Vette (1995 Vert) because we have no crossover pipes. It was a dual 3" in and out and fits almost perfectly in the stock location. Our 2 3/4" exhaust fits it well. Sounds killer without the annoying drone that's common to most exhausts. I did go with the Borla resonators right befort the tail pipes.

I have ran the Impala and the normal times are 11.6 @118 MPH. The Vette is about a thousand pounds lighter and should be in the mid to high 10's and still be perfectly streetable and ready for a long road trip if you'd like. I have all the part numbers for my build and if you'd need anything just let us know. I also have all of the parts that didn't work as well or not at all. That list is long and distinguished. Someone on here will have an answer. Good luck with the build and remember to keep it fun,.

 

[1963SS]

I could really CHOKE the guy at GM that decided to bring back the LT-1 and LT-4 designations!!!

I'll bet the guys that have the early 70's LT1 said the same thing when our LT1's came out. :laughing:

I'll dig up a couple of build sheets for you and get back to you this week. The stock opti is the best option. I've known several folk that have had the MSD fail after a very short time. You can check with the folks at Torquehead for a 24x conversion kit that does away with the Opti completely or the Bailey LTCC kit is a bunch less expensive and removes all the high voltage from the Opti. No carbon flying around and no ozone from the high voltage keeps the optical sensor a lot cleaner. I've never had a failure with the LTCC installed.

You really won't need the monoblade. Just a good 58mm will do the trick. A 48mm flows about 750 CFM, 52mm about 850 CFM and a 58mm is about 1000 CFM. Monoblade probably isn't the best option. A bigger concern would be the MAF that flows just over 700CFM. It's going to be the limiting factor on a big horsepower engine. It may be reasonable to just get a 58mm and then get a speed density tune. That will do away with the restrictive MAF.

I run electric water pumps on all my (3) LT1/4's. I use the Meziere that is 55 GPM or whatever. It's the biggest one. It does a great job at the track and keeps the engine cooler when idling in stop-and-go summer traffic in the hot cities. I've never had an electric pump failure even though I do carry a spare.......just in case.

Good choice on not using the aluminum rods. I've never used them for reasons of longevity and also because they typically have more "meat" on them and I was concerned about clearance issues with the 383's.