Can you modify L31 Vortec heads to work on an second-gen LT1?
 

Does anyone have a good idea as to what kind of machining work would be required to make L31 Vortec iron heads reverse-flow capable for use on the second-generation LT1?

This question I pose is a research effort into a future engine build to give me the kind of performance I seek out of my LT1, dedicated street car performance, nothing impressive in terms of horsepower but definitely focused on low to mid-range torque production for a smile inducing daily driver at the green traffic lights.

I understand there are better head designs out there but I am trying to focus on what I can do with various bolt-on parts while using a factory camshaft. If the Vortec iron heads were supposed to be the last evolution of the LT1 heads, much more improved and combining features of the LT4 heads, and they are a performance part for first gen SBCs, then I have to explore how to get these heads on my LT1 if it is possible and for my notion of performance, maybe worth it for the grin and seat of pants feel.

Not worth it at all.
Find some iron LT1 heads from a Caprice, Roadmaster, or Fleetwood, for identical performance to the Vortecs. They tend to have just a smidge better intake flow and slightly less exhaust flow than aluminum LT1 heads. Personally I'd stick with the aluminum heads.

I have considered that, but again, there is a reason why I am looking at the L31 Vortec heads for my LT1, it would make it much more easier to put on a TPI intake using the Scoggin Dickey Vortec TPI base. The more I have researched, from stroking my LT1 to using a supercharger, and then coming to the realization that it's too much power for the driving I do, and especially for winter driving, I really want something reminiscent of a TPI L98 but using my LT1 to build off of.

I want my own "torque monster" to unleash at the change of a green light, not for racing, not for bragging, but just to enjoy my car more within the confines of a modified stockish set-up that won't destroy my rated city mileage, won't add to emissions but give me what I seek, low to mid-range seat of pants feel that I can enjoy once in a while. Really, "practical" daily driver performance that is affordable and won't destroy my savings. So, with this all said, either I spend the money to modify a TPI base to fit LT1 heads, iron or aluminum, or I spend the money to get Iron L31 Vortec heads to work on my LT1 and then easily put a TPI intake on my LT1, one with AS&M long runners that was extrude honed and polished.

I know I am in the minority with this build idea but it best suits my needs and wants out of my engine.

I'm sorry, but this post seems bonkers. We're you the one who wanted to put a TPI I take on an LT1 a few months ago?

At that point, why stick with the LT1 and not just pick up an L31?

It seems rather silly to keep the LT1 block when everything else is going to be SBC anyways.

Install some 3.73 gears and a tune.

Seriously!

KW

Yes I am that bonkers guy who suggested the outrageous notion of putting a TPI intake onto an LT1, and after exploring the options from stroking the engine to supercharging the engine, I come back full circle to wanting a TPI set-up. What I want is essentially a second-generation TPI SBC. So, is this bonkers? That is personal opinion. Why would I have a track car built when I don't go to the track? Why would I have a high horsepower car built when I can't enjoy such power on speed regulated streets? To brag? I see this in terms of practicality and trying to get more enjoyment out of my car by being able to use torque off idle and in the mid-range up to 5000 RPM. The TPI intake is a natural fit. I don't see why no one understands why I want to have this done.

I don't want to spend the money to purchase a turn-key L31 and then spend more money to have the thing swapped into my car. For that expense I can have L31 Vortec heads modified over to reverse-flow capability to work on my LT1 and even have money left over to extrude hone and polish a TPI intake with AS&M runners on the SDPC vortec base. I have already spent the money on the block and internals for my LT1, I want to salvage what I have but have the block modified over to a TPI.

I won't be happy with that. Yes, it is the simple solution but a solution that won't make me happy. I prefer my stock gear ratio in the M6 and I want low end and mid-range torque. So, why is this hard to understand? It can't be done? I doubt it very much. It is just that for some reason what I want to do is frowned upon and I can't understand why, for a daily driver, this is a practical performance set-up that I can enjoy from every green traffic light, not the track light.

I would use a set of ported LT1 aluminum heads and a ported LT1 intake. Add a CC503 cam and you'll make nice low end and top end power with a sweet sounding car (assuming full exhaust). KISS - keep it simple stupid...

The longer the intake runners the higher VE at lower RPM. If you want torque then get a TPI (or LPE SuperRam if you can find one) with an RV cam and you'll be able to pull out a Nebraska Oak in Serbia in the middle of January at 200rpm...

Stock exhaust. I am regretting ditching my factory exhaust manifolds for the Hooker shorties I bought. I am seriously considering buying improved reproductions from a racing parts manufacturer who offers them and in which they can be bolted onto first gen SBCs due to extra drilled holes. I don't need long tube headers and I am not willing to have the exhaust reworked to fit catalytic converters on the car. Plus, with the pot holes around here I am going to tear apart the flanges if they are dangling as low as they will. The set-up I want will be stockish, and my choices for camshafts are the B-Body LT1 cam, my stock camshaft, or even the ZZ4 camshaft. That is it. Yeah, I could have shorter rear gear ratio to rush me to higher RPM level to tap into the LT1 power band, or I can spend money to have this TPI conversion where I can drive around town in low RPM but have plenty of torque and when I do open up, I can get my thrills from the new torque curve up to 5000 RPM.

Thank you.

Stock LT1's make great torque down low. That's why I kept my '97 SS for so long before getting into the gen III engines. If you already have an LT1, just use it more or less as is. If you are already restricting yourself to shorty headers, stockish cam, etc, then I would suggest to keep it simple. I would hate to customize everything within a narrowly self-restricted parts list, only to have a full bolt-on LT1 run away from me in a race.

Wow...where to start

So you want L31 heads to run a TPI on the LT1 to make a low end TQ monster...assuming it would become that with just the head and TPI swap. Man unless you are a machinest and have a shop the cost, assuming it would even work or could be done, if you have to pay to get this done is HUGE compared to just putting in a small "RV" type cam, PCM tune.

Assuming your M6 has 3:42.....you don't want to change gear ratio but going 4:10 would WAY wake up off the line driving. With a 27" tire I am at 1990 RPM in 6th at 80 MPH so fwy driving is nt gas guzzling high RPM.

Nothing wrong with blazing your own trail, being the only one, etc.....but from your posts saying you just want a street car that has great low end TQ, is emission friendly.....a cam with even stock heads would do that and be way cheaper to do. Even mildly ported heads for more power.

Well, I don't need a full bolt-on LT1 to show me up on the street these days. Besides, I have always wound up with a state trooper or local PD cruiser checking my car out when I wasn't doing anything reckless while others have blown by me on the expressway doing better than 80 mph. In my world, if I want to race or go fast it has to be at the track. I haven't made the track a hobby and had I decided to engage in the automotive mechanics trade I may be doing things differently with my car, or not.

I just have a wicked obsession with torque production without the need to rev the engine at high RPM. This is why I am at this point researching and contemplating this build. My stock LT1 never impressed me but then again I was never maxing out the rev limiter to seek my thrills. When you have a cop pull you over for a bogus suspicion of me leaving a bar and then issuing me a bogus ticket for running a red light when the light was yellow as I passed it, you will adjust your habits real fast after getting slapped with points on your license. Being a former 18-wheeler truck driver, in order to keep my license clean I can't get marks on my license. So, if I have to respect speed limits and drive slow, low and mid-range torque production is what I will be seeking. So, here I am.

Okay, I will think about this suggestion. However, when you suggest ported heads for better air flow and a cam for my torque requirements, I automatically think of the B-body cast iron heads and camshaft. Driving a lighter car than the Caprice/Impala and Fleetwood/Roadmaster, it should give me a taste of what I am seeking. However, I would want to go further and this is where I dive into the L31 Vortec heads and TPI intake with large runners and extrude honed and polished. From what I figure, the L31 Vortec heads need to have the intake side coolant passages welded off with steel and sanded down to flush while on the flip side the block mating surface needs only to be gasket matched. This level of work shouldn't break my bank unless the standard flow heads totally have a different set-up than my reverse-flow set-up. After that I only need the Scoggin-Dickey Vortec TPI base to use the TPI intake. After that, I am not sure if the B-Body LT1 will be all that I need or if using the ZZ4 camshaft will be an improvement over the B-Body LT1 camshaft while still working within the lift restrictions of the L31 Vortec heads.

Yep.....my bad. I assumed (bad thing) that you had an auto. You install the gears and you will have ridiculous throttle response, and for a lot less $$$$ than a heads/cam install.

My 96 Impala has 4.10 gears and my 95 Impala has 3.73 gears (both 4L60E trannies). The '96 Impala has a bit less power to the wheels.....but it's WAY more fun to drive.

Best of luck with whatever you do!

KW

Dude Find a 400 SBC and Stroke it to a 434 then put Vortec heads on that with TPI & use a small cam thats Done by 5000rpm & BAM TQ Monster!!!

And do a Straight Pattern 206 @.05 .480 110 , 212 @.05 110 or a Lingenfelter cam thats 211/211 or 219/219!!!

i can't answer any of your questions. just wanted to say I'm rooting for you. i want to see your ideas happen :corn:

If you're that dead set on getting a torque monster, take the advice of the guys who've been at it longer than you, insteading of looking the gift horse in the mouth. Small cam with good lift. Gears. Bolt ons. Tune. Or better yet, skip the cam, because by the sound of it, if you're running shorties, you still have a number of mods to do before you're at the point where you should step up to a cam.

Don't just throw old-school parts at it to make it faster, that's how you end up with an awful engine for a lot of money. If you are that dead set on making it have more torque, get yourself educated on what basic bolt ons you don't have, and how cams work so you know what kind you want.