The Stovebolt Site Forums The Shop Area Engine Shop 235 and performance

I've done a search on upgrading to a SBC Vs. keeping it stock. My 235 is going to be doing a lot of towing of a trailer weighing 11000 lbs loaded up and I'd like it to keep up with the traffic. I hear plenty saying keep the inline 6 but I need min 350 ft/lbs and 300 hp and plenty of reliability for adequate towing performance. Who here has gone down the inline 6 upgrade road and what has it cost to get something near basic SBC performance and reliability?

A 235 will pull your trailer at a slow speed with low gearing.For road work at hiway speeds with a 11,000 lbs trailer, you need power that at least twice what a 235 can make even if modified.Sounds like a big block V-8 is the choice.

A built 235 will handle up to 5k trailer with a 5 speed. You are pulling 11K at speed go V8. A 350 would pull your load just fine!

Run a gear ratio between 3:50 and 4:11 for your gcvw. Prefer gear splits of a 5 speed trans but autos work well also.

Thanks all, started looking at a few donor Suburbans. There are EFI 5.3l, 350 and 454's to choose from as well as the vortec 6.0 that's still a little new and on the pricey side. Since I will probably need to redo the electrics in the truck I think I can plumb in EFI and I want to stick with a manual transmission. Any suggestions on what engine out of those would be best? I am not really sure torquewise whether the 350 will be enough or not. Did start to have a look at a few big straight 6 diesels (Izuzu that GM makes under licence) but they're also rare and pricey.

You know, if you're V8-ing the truck anyway, you might consider a BOP 455 engine. Small as a 350 but torquey as a 454. They weigh considerably less than a Chevy big block too. With the right cam, and a good compression ratio, you should be able to get 600+ lb-ft out of them. I've even seen BOP 455's approach 700 lb-ft at under 2000 rpm. That's pretty good torque and should make an outstanding tow motor.

...Muncies will bolt right up to them too, as well as a host of other transmissions. Richmond and Tremecs to name a few.

Thats a good idea Hot Dad. I take it you are
refering to the Buick version as the pont. &
Olds are heavyer.

The Bue is supposed to be the best of the 455's, but any of them will work as well, and make very close to the same torque. I've got a Poncho 455 in my Firebird and it's a hellraiser.

My understanding is there is an aluminum Pontiac 455 block for sale now, if you want lightweight torque. It's sold by Indian Adventures if you want to do a search on it. I seem to remember that it was around 3.5 grand, cheap for an aluminum block.
That would look pretty cool if the block and heads were polished as well as the manifold!

For me it would be a no brainer...I've always wanted to put a 5.9 cummins turbo diesel in a pickup(other than dodge). I've seen a school bus sell for $1800.00 that had the best of both worlds a 5.9 and an Allison(545 I think). If you consider this consider getting a Cummins between the ages of about 94-98 they have a bosch in line injector pump called a p-pump. It's my understanding you can get alot more out of them affordably. It would be ideal because in our throw away world they are selling alot of busses this era now. I think this would be fairly simple to do if you had enough room. It would surely complicate matters to get a newer 5.9 with the electric fuel rack I would think. One of my friends already beat me to the punch(no pun intended) and put a 5.9 in his 90 or so chevy 1 ton. He used his orig. 5 speed though since he hadn't thought of the school bus idea. He paid $2,000 for the engine only.Watch for ford or bluebird busses.

Since we're also talking weight, can anyone tell me what the 235 weighs so I can compare it with the options out there. Sparkie what about the current GM straight 6 turbo diesel that powers the smaller trucks, has anyone used one of those? From what I have found so far the EFI 454 is selling for less than the SBs that the junkyards are parting out of Suburbans but I am thinking the conversion would be a bit more work than a SB.

The 216 and 235 weigh 630 pounds. By comparison, a Buick 455 weighs 600 lbs, Chevy small block weighs 535 lbs (alum. intake) and Chevy big block weighs 685 lbs (all iron).

the other concern would be clearence...

I am thinking about (longterm) a diesel swap for my big bolt. lots of good info here.

-Mike R

I'm a fan of the big block approach. But then I had a big block Impala when I was a kid and want to return to my childhood...

I have a 454/400 turbo combination from a motorhome. The GVW is rated at 13,000 and it was rated to pull quite a trailer. I stare at a computer all day long, and like the idea of avoiding them when I climb in my truck, so the big old gas powered approach has a certain appeal.

can you say HEMI

Albatross, I'm not sure which gm engine you mean. The duramax is a v-8......to complicated. In the kodiacs(I have one) and other big trucks they used a caterpillar 2116 coupled with the same allison 545 a school bus uses. This combo would be good but I think it's (at least it looks) bigger than a 5.9. Lets remember these old stovebolts have a LONG nose and a solid axle. I'm pretty sure there would be a bigger area than a 1990 chevy pickup has. I don't know the weight of a 5.9 but it can't be more than a couple hundred pounds more than a 235. Since you have leaf springs, they could be stiffened if necessary. Remember a 5.9litre is the engine in some 2500 ram pickups, and capable of producing far more than 300 hp. and torque... off the scale! Not to mention GAS IS 2 BUCKS A GALLON!!!And you only have a 15 gallon tank. It doesn't seem fiscally responsible these days to try generating big hp with gas. I don't know about you but 10mpg or less doesn't appeal to me.
Allow me to reiterate.....school buses sell CHEAP!

Forgot something.....There is a reason why all the semi trucks these days are turbo diesel. A gas engine can't come close to the fuel economy. A 5.9 of the era I mentioned would be so simple to wire...starter wires.....alternator wires....a push button for th fuel shut off cylinoid...water temp...I thinks thats it . Don't get the impression that just because a school bus is big it must have an enormous engine. Think about it, its not really hauling or pulling anyting except a bunch of kids and I'm sure it's not designed to set any land-speed records either. I would have already done this but I still havn't got a good idea of how to gear it up....not good to have a diesel running too many revs. Anybody know what the gear ratio is of a dodge cummins truck? Or if the overdrive transmission compensates?

The 5.9 cummins is about 1k lbs. My 2002 dodge was avaiable in either a 3.54 or a 4.10. I think the newer ones are only 3.73. The NV4500 5 speed is 0.75 and the NV5600 6 speed is 0.73. The NV4500 weighs 250lbs and the NV5600 weighs 360lbs. You may be able to make it work in a larger truck but I think it is too heavy for a pickup.

The most cost effective route is a small block chevy. The extra cost to put in a diesel will buy a lot of gas.

If you decide to go with a gasoline engine, stick with the BBC. 454s are plentiful and reasonable, and hold up well to HD use. It will do fine without a lot of expensive aftermarket performance upgrades. I don't know, however, how well it will fit in your truck. I have done a lot of towing; I don't think you will be at all happy with the performance of a 350 pulling an 11K lb trailer, especially if you want to "keep up with traffic".

All good stuff, the diesel I was talking about is the straight 6 that is/was an Isuzu design that has been somewhat overshadowed by the V8 duramax, it features in the smaller trucks and is around 300 cu/in. I will have to do some more looking into it all, I agree that I can throw together quite a high torque BBC pretty cheaply and EFI wouldn't be a problem but there is a certain appeal in a diesel. It's only getting used maybe twice a month so I am not so sure if the extra work in fitting a diesel would be worth it in the long run.

Would this work in a half-ton C10, if I wasn't going to do any trailerin'? Deisel