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Discussion Starter · #1 ·
Hello there. So right now I'm just doing some planning. Right now I've got a 1972 Chevelle with a good running 350 and a automatic trans. I believe it's a TH350.

I want to convert it to Manual Transmission. I'm thinking a Muncie 20 or 21. If anyone has a used one they're selling let me know. I live near Chicago.

FOR THE ENGINE: I want something that can push around 400-500 HP nothing crazy. Should I keep and rebuild the 350 or should I maybe go big block. Supercharger? Tell me what you all think. To be honest I'm on a budget so what would be the most cost efficient overall.

Like I said this is just to get me thinking.
 

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Hello there. So right now I'm just doing some planning. Right now I've got a 1972 Chevelle with a good running 350 and a automatic trans. I believe it's a TH350.

I want to convert it to Manual Transmission. I'm thinking a Muncie 20 or 21. If anyone has a used one they're selling let me know. I live near Chicago.

FOR THE ENGINE: I want something that can push around 400-500 HP nothing crazy. Should I keep and rebuild the 350 or should I maybe go big block. Supercharger? Tell me what you all think. To be honest I'm on a budget so what would be the most cost efficient overall.

Like I said this is just to get me thinking.
Budget AND hp? Good luck! Must have a big budget!:smile2:
 

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It's usually better to start with a performance goal rather than a horsepower number. How quick do you think a 500 horsepower Chevelle will potentially run? Do you have the budget to upgrade the rest of your drivetrain? By the way, what is your budget?

Starting out, especially if you are in a budget, shooting for something that will push you back into the seat is a reasonable goal.

Steve R
 

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Discussion Starter · #4 ·
The HP was just an idea to help. Let's talk 3-4K to put into the drivetrain.

I guess a better question is, would it be better to keep the 350 SB and rebuild around it. OR sell the 350 get a used big block and rebuild around that? Or even maybe the oh so popular LS swap.
 

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Get some performer RPM heads, Air gap RPM intake, The matching RPM cam and a Demon 650 carb. Bolt on your 350 and you will be pretty happy. I put that setup on a 350 I had and man was it an upgrade. Not many people use that cam but I liked it. It was like a shot of nitrous at 3000 rpm and pulled hard to 6500. You can't go wrong with a kit designed to work together. It is reasonablely priced and easy to do for someone who hasn't built many a motor. You might have enough $ left over to do the trans swap if you can find a good deal.
 

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After building a couple of quality 383's, $3-4K probably wont get you there. Upgrade the 350 with some good heads, cam, headers and carb and enjoy the ride. You can always upgrade later if it doesn't get you where you want to be.
 

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Hello there. So right now I'm just doing some planning. Right now I've got a 1972 Chevelle with a good running 350 and a automatic trans. I believe it's a TH350.

I want to convert it to Manual Transmission. I'm thinking a Muncie 20 or 21. If anyone has a used one they're selling let me know. I live near Chicago.

FOR THE ENGINE: I want something that can push around 400-500 HP nothing crazy. Should I keep and rebuild the 350 or should I maybe go big block. Supercharger? Tell me what you all think. To be honest I'm on a budget so what would be the most cost efficient overall.

Like I said this is just to get me thinking.
This is more process than specific but I'd take the task on in steps.

First, I'd decide in what rpm range I wanted my eventual engine to run effectively. A high rpm screamer can be a lot of fun, but they can be quite temperamental on the street. An engine producing low end torque (my recommendation) is typically more street 'friendly', and more budget friendly. Everything (transmission, rear, exhaust, etc) all depend on the rpm range desired.

Second, I switch to the manual (wide ratio, if you'll be operating within the lower rpm range). Then, re-asses your engine and see where you are. You may be closer to your 'performance' goal than you think. A lot will depend on your rear gearing. Your car WILL be more fun to drive (in my opinion).

Second, if your are 'almost there', some tweaks to the 350 might be cost effective.

If more 'more' is desired, I'd look to add displacement. A 383 can be built from your 350 rather cost effectively, especially if you build it for low end torque and keep hp goal to approx 1 hp per cu in. A mild 383 in the 400 hp and 440 lb-ft torque range is a very friendly street engine and likely as budget friendly as it's going to get. You certainly can get a little, or a lot 'more' out of a 383. The costs go up accordingly.

If really not close at all, drive the car the way it is until you can save enough $ to knock your socks off with a big block.
 

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Discussion Starter · #9 ·
Thanks japete92! Lots of good info from everyone. Yea I'm leaning towards low end torque from a 383. I do drive it pretty regularly and high rpm performance isn't necessarily my priority. I am more likely to something more towards a top end kit. Just to get that extra oomph out of the 350 and see how it goes.
 

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Probably worth make the small block or big block decision first. The oil pan, headers, intake and brackets have to change when you go big block.

If you are going to stay small block, and your short block is sound, just do heads cam intake, etc. Moving to Edelbrock or AFR heads with a matched cam would make a world of difference.

In my case, I had rebuild the 350 to work with a stock torque converter TH350. Then I put in the five speed tko. That made the car lots of fun, but the cam did not want to go over 4500. It cruised ok, but the 308 gears just did not make it go. So in went a 373 gear. Now the cam is really poor.

So I upgraded the cam and better valve springs. Now its a blast to drive, pulls to 5500 and still cruises down the highway at 2200 or so.

Point here is to match it all together. I did it in stages as funds and time permitted. And I have a 454 sitting in the garage.....
 

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Get some performer RPM heads, Air gap RPM intake, The matching RPM cam and a Demon 650 carb. Bolt on your 350 and you will be pretty happy. I put that setup on a 350 I had and man was it an upgrade. Not many people use that cam but I liked it. It was like a shot of nitrous at 3000 rpm and pulled hard to 6500. You can't go wrong with a kit designed to work together. It is reasonablely priced and easy to do for someone who hasn't built many a motor. You might have enough $ left over to do the trans swap if you can find a good deal.
You can absolutely go wrong with that kit....and I'm a huge Edelbrock fan. The FT SBC RPM cam will indeed rev past 6K RPM...with the proper valve train pieces. However, it sucks on the bottom end, barely makes enough vacuum for power brakes and will absolutely need a torque converter update.
 

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The answer to the OPs question is: Do NONE of what you are pondering....for now.

That the OP can not identify the transmission type means that he needs more experience and knowledge.....which will come with time. A swap to a manual tranny is likely out of his current skill set...and probably his wallet.

For RIGHT NOW, change nothing to your drive train...at all. Instead, tune your carb and distributor. Learn how to do a basic tune up. You will absolutely need these skills down the road....unless you want to pay someone else to do them for you. Once you've done what I'm suggesting, slowly upgrade the 350 in the usual, time-tested Hot Rod style. You've got to walk before you can run.

BTW: on the tranny - 1) first verify that you have three forward gears. 2) after doing that, does your tranny pan roughly resemble the shape of Texas? If so, you have a TH-400. If the pan is mostly square except for one angled corner, you have a TH-350.

A modest 350 small block that is properly tuned, TH-350 tranny, and gears 3.08 or better will easily get you into the mid-14s. Some time and money will get you into the 13s. See my sig - I got into the 12s...with a turd ferguson convertor.

I'm not being mean. You're new and need to learn. If you stick with it, you'll do fine. These cars are not Ferrari 355s. Very easy to work on.

Best of luck....and welcome to the hobby!
 
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