Inliners International Forums General Discussion Hi Performance Chevy II fourbanger modifications.

I would appreciate hearing from anyone who's combined parts from a Chevy II 153 and the newer 151 to make a 163 cubic inch engine. I believe you use the 153 crank in the 151 block for an extra 1/4" stroke.

A member discused this proceedure with me a while back, but I can't remember his name. He used to run this combination and said it was a hot set-up. Can anyone help me out, here?

You can also use the 3.6 inch stroke crankshaft from one of the older GM 181 cid engines with the two-piece real main seal. In 1989, GM changed the design to use a one-piece external seal similar to their V-8 engines.

You will have to use the Chevy/Pontiac 2.5 liter (151) "R" code block with the two-piece rear main seal and a distributor. These were found in pre-1985 GM rear-drive cars like the Monza, Sunbird or Fiero. The use of the 153 or 181 crankshaft might require a seal adapter...sort of two cresent-moon shaped seal halfs. Check with Billy Page Sr at 903-569-6311. Also, you will have to use the wider connecting rods on these crankshafts too as the journal is a 1.048 by a 2.100. You can machine them to accept a narrow GM V-8 small block rod.

Depending upon your budget, accessability to parts and machining, and your performance requirements, I suggest you look for engines already converted or for the race version GM/Pontiac engine...the Superduty-4. I've got suggestions but cannot openly discuss them here in the forum.

Regards,
Gerry Dedonis
dedonis@kans.com
Kansas Racing Products Inc. http://www.kansasracingproducts.com

------------------

Thanks, Gerry

I have two GM 151s. One came from an '82 Jeep CJ5 and the other one came from what I think was a '79 an AMC Spirit. They both have Chevy I-6/SBC bellhousing flanges. I haven't torn them down, yet, but believe they have the split rear main seal type.

I also have a '69 153 (3.25") crank and same year head with 1.94 intake and 1.69 exhaust stainless swirl-polished valves. The head has been pocket-ported, but with no radical port work.

I'd thought of using a 151 block, with the crank and head from the 153, to build a 163 inch engine. However, I don't know which rods and pistons to use.

I built a Mercruiser/Chevy II 153 engine for a Chevette. It was fun to drive and had a lot of zip, but this is the first time I've thought about mixing parts to come up with a bigger engine.

I've read about the heavy-duty blocks you have and if I wasn't retired I'd HAVE to have one! As it is, I have to do a lot of scrounging, like when I was a kid.

Thanks for taking time to answer. Dennis

I had failed to mention that the GM 2.5 also came in Jeep products until the early 80s. Then AMC-Jeep went to their own 2.5 engine. In my opinion, the 2.5 is a better choice as it allows the use of cross-flow heads where the 153 and 181 has a high-mounted distributor. GM-Pontiac still offers performance aluminum heads made by Brodix and an aluminum manifold.

I've also got new and used parts along with access to two Pontiac Superduty performance engines. One is all-aluminum and the other has the iron SD block with aluminum head. Both are 166 cid. You might be surprised at the reasonable cost of Superduty parts and older engines. Send me an email if interested.

Gerry
dedonis@kans.com

------------------

Dennis,

I'm writting from Brasil, here we had for a long time this 2 engines, the 153 like the U.S. built and a 151 quite similar, but I just don't know if there is anything quite like it there.
I've assembled some 3.250" cranks into 151 engines sometimes, no big problem. Our 151 has 6.000 long rods, and the 153 has 5.700, both cranks have the very same 2.000"/2.300" journals, so no sweat here. The deal is: use the 3.250" crank, 5.700" rods and 327 Chevy V8 pistons. Or use the 6.000 rod and get a set of 350 pistons, mill the top a li'l, and you're thru. I do strongly recommend using forged pistons like trw 2403, that are stronger than the cast ones. But if You have acess to a 181, I see no point in dealing with smaller engines. The 181 head is quite superior, has non-siamesed intake ports, that may be a bonus if you may want a better milleage, it'll give a stronger pulsation in the intake, making easier to start the main circuit of the carb. The only drawback of the 181, that would make some sense using he smaller motor should be the vibes, the 181 is somewhat harsh, the 6.000 rod 151 is quite smoother.
Hope have helped.

Thanks for the info, Alex.

I've seen some neat cars made in Brazil, in magazines, but have never been there. Of course, everyone knows about Rio!

As for engines, my problem was solved a couple of weeks ago. I found a nice Mercruiser 181 at a reasonable price and bought it.

The engine had spun a rod bearing, but the engioe had been stopped immediately, so the crank cleared up at .010/.010. That surprized me and the machinist, too! The engine had a slight wear pattern in the cylinders, but .030 cleared the bore up nicely, too.

I should have the engine running by this time next week. Thanks again for your interest, Dennis

Dennis,

You did the right thing. The 181 is by far and large the best performance option for a GM four banger. Neat li'l engine! Gasoline has always been too expensive here, so smaller engines are popular. It's much easier to find the smallest engine choice in cars with such an option. The opalas came with both 4 and 6, the 4 ones are more popular.