Thread: Modernized Chevy 302 build

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Howdy folks, I was hoping someone could give me some advice on this. What I'm looking to do is take a 350 block with the 1 piece main seal, stuff in the crank and connecting rods from an L99, and cook myself up a Chevy 302. I'll be building this from the ground up. new push rods, rockers, everything. This will ultimately replace the wimpy 305 in my car (86 Trans Am) now. Has anyone here built one of these combinations before? If so, just what exactly could it do?
I figured something like this would be up a hotrodder's alley, so I was hoping I could find out even more information here. Thanks in advance folks!

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You can use the one piece seal block for the roller lifter features with an pan adapter to use the earlier crank-you'll need the later 302 crank for the main bearing size or use the thick adapter bearings that may still be adaptable--------I once buit a dirt track engine with the 302 crank in a 400 block that was a killer----not too much torque off the corner and would rev to the top======championship winner

Welcome! There's a few here who can give step by step details that you can trust. Glad you're here.

Originally Posted by Reborn756

Howdy folks, I was hoping someone could give me some advice on this. What I'm looking to do is take a 350 block with the 1 piece main seal, stuff in the crank and connecting rods from an L99, and cook myself up a Chevy 302. I'll be building this from the ground up. new push rods, rockers, everything. This will ultimately replace the wimpy 305 in my car (86 Trans Am) now. Has anyone here built one of these combinations before? If so, just what exactly could it do?
I figured something like this would be up a hotrodder's alley, so I was hoping I could find out even more information here. Thanks in advance folks!

I don't see the advantage. The L99 crank will bolt into the early 350 block, but usually if someone does something like this, there will be an advantage in rev range or higher static compression ratio running better fuel in a race configuration. But in this case, the crank is cast, so there is no rev advantage and the currently available pump fuel quality will not allow much over 10.0:1 static compression ratio due to detonation, so it looks to me like you'd be throwing good money after bad just to say that you have a 302 in the car. If your goal is to improve performance in that 3500 lb car, bolt a 383 kit into your 350 block, along with a set of 195cc Pro-Filer heads, Edelbrock Performer RPM intake, 750 carb, 1 3/4" equal length headers. You'll make 500 hp, 500 foot pounds of torque and life is good, and you can tell everyone it's a 302.

Here's a link to using the 3" crank though, if you're just hard-headed....
New hope for my 302!!! - Car Forums and Automotive Chat

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Thanks for all the replies folks! The reason for the 302 is because everyone and his cousin has 350/383/LS1 swapped third gens nowadays. A Chevy 302? Most people have no idea that even exists. Sure, a 350 would be a lot more practical, but the 302 will be a unique and fun little motor. Playing around on Desktop Dyno and Camquest6, I've found that by using cams such as the 260HR, 270HR, and 280HR, you can make the power band on this motor much more street friendly. Also, I do honestly suspect that this motor would be a lot nastier than the smog 350s, even in factory L98 trim (minus cam connecting rods and crank, naturally)

It will without a doubt let me smoke any factory 90s and older 302 'stangs out there

Like Tech says, why not bigger? Since a 302, 350, 383, 400, 265, 283, 262, etc all look pretty much the same outside AND building a motor costs about the same regardless of size, build the biggest and call it a 302. Besides, nobody but you gives a darn how big or little the motor is unless someone is doing a tech inspection for a class with rules. Sure, a 302 might rev higher with the 3 inch stroke, but revs don't get you to the finish line first or lift the wheels higher.

Thanks for the reply robot!

My uncle said the same thing. Build a 383, slap some custom covers on it that say 302. Simple. I just can't bring myself to fib like that. If somewhere down the line I would happen to get into displacement limited racing, I would have a 302. Also, since this combo consists of only the L99 Crank and connecting rods, a skilled mechanic could turn it back into a 350 in a weekend. Sorta like two motors in one. In fact, if I do end up going the 302 route, I'm going to dyno the setup as a 350 and as a 302 just to be able to compare numbers.

Here is some info....in 1969, I ordered a 1970 Camaro Z/28. Chevrolet was slow in coming out with the new Camaro body (that's why you see it referred to as a 70 1/2 Camaro). Mine arrived at the end of February, 1970.... it had the 350 LT1 engine. I had a buddy take me up to Denton, TX to pick it up. (my price was $3376 total). I needed to fill the tank before I drove it back to Dallas so I stopped at a Conoco station. The guy at the station had a 69 Z/28 with a "for sale" sign on it. It was less than 10 months old and had something like 6000 miles on it. So, I told him I would come back the next day and buy it. I did.
So, I had a 350 Z/28 and a 302 Z/28 at the same time. Same rear tires, same close ratio Muncie, same Holley.....the 350 would beat the 302.... even if I started out in 2nd gear in the 350. The 70 was heavier than the 69 but the 70 was faster. I tried racing my buddy (he drove one of my cars and I drove the other) Regardless of who was driving either car, the 70 always won.
48 cubic inches is significant.
Build a big motor.....you don't have to blab the size, just smile.

Since almost all gen 1 small blocks look basically the same I think those guys are right its only in name unique not in looks or performance, if power is what your after go for the 383 Tech mentioned, I guess if unique in name is what your after go for it. if you just want to spend money to be unique in looks and not name go see Nick Aria Jr for heads! Its hard to be different with a small block, but they run wonderful!

Thanks for the replies! Without a doubt the 350 would beat the DZ-302. Those cars were absolute dogs until you had them wide open. By then the 350's already in 3rd gear half-way down the track. The 30-30 duntov was just WAY too much cam. if my calculations are correct, a smaller cam, such as the 270HR, will give you a much more streetable power band. The 350 still makes more hp and torque (especially low end torque) but the "L98 302" as I'm going to call it, isn't too far behind. Will a mild 350 still beat it? No doubt. Will smog 350s from the 80s beat it? probably not. It will be a fun little project however. This car is just a toy. When I eventually sell it I'll be going with a motor with more cubes. Right now, it's going to get abused

I would say build what you want. Then report back and tell us how well it works. Then re-read all the posts and see if you made the right decision.

Originally Posted by Reborn756

Right now, it's going to get abused

Just remember, the crank is cast, not forged.

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we told you so--------------------

Originally Posted by Reborn756

Thanks for all the replies folks! The reason for the 302 is because everyone and his cousin has 350/383/LS1 swapped third gens nowadays. A Chevy 302? Most people have no idea that even exists. Sure, a 350 would be a lot more practical, but the 302 will be a unique and fun little motor. Playing around on Desktop Dyno and Camquest6, I've found that by using cams such as the 260HR, 270HR, and 280HR, you can make the power band on this motor much more street friendly. Also, I do honestly suspect that this motor would be a lot nastier than the smog 350s, even in factory L98 trim (minus cam connecting rods and crank, naturally)

It will without a doubt let me smoke any factory 90s and older 302 'stangs out there

You go Reborn! anyone can drive a torque motor and being different is what Hot Rodding is all about.I too want to build a little revver or even a de-stroked 400.push in the clutch and rapp it off!