The Stovebolt Site Forums The Shop Area Engine Shop Getting more horsepower

What are my options for getting a little more horsepower out of the 350 in my 72 5500? Say 50 or 75 horsepower are new pistons available for the truck engines

A 427 truck engine?

A rig that big, hauling what you are hauling is asking a lot out of a 350. You can get more horsepower out of a 350, but there is no such thing as free lunch.
More torque is what you need. That's where a stock big block comes in and shines.
The cost of souping up a 350 would be better spent on a decent stock big block in my opinion.

Buy a crate 454

"Horsepower is to brag about- - - - -torque wins races!" That saying is also true concerning hauling heavy loads. Anything you do to bean up a 350 will put the power gain at the high speed end of the power band, and that's not where a big rig needs a boost. Low end torque is what gets a load moving, and also delays the need to downshift on a hill. A 454 will do a lot more for you than hotrodding a small block, or a 2 speed rear end will come in handy if you want to keep the small block in place.
Jerry

Big block would be best. But the small block stroker kits are super affordable nowadays. You could build torquey motor with one of those and the right cam.

I have gotten 600+ HP from a small block (real dyno figures, not bench racing pipe dreams) but the engine only lasted about 1,000 laps around a 1/2 mile banked oval track. If you're willing to rebuild the engine about every 500 miles, go for it!
Jerry

The 454 was overrated, but enough aftermarket engineering talent and money was put in to alleviate most of its problems.

Back in the '90s when the mountains around SLC told me I needed more power than the clapped out 327 in this bus could give me, I started looking for more gumption under my right foot. So of course the first thing I did was look at big block Chevy engines. Every 427 truck big block seemed to be in a wrecking yard with spun main bearings, sucked valves, and other issues. And a buildable core was $2500 in 1994 dollars.. everyone wanted a 454!

I had a yard full of Cadillacs. Their sturdy V8s made more torque than a 454, at lower RPM, and the bottom end was actually designed to be 500cid. Its high nickel alloy content block and heads are 150lbs lighter than a BBC; a 500 Cad with an Edelbrock aluminum intake weighs about the same as a small block Chevy. Fun fact: GM actually envisioned the big Cadillac V8 to be capable of 600cid, and then OPEC oil crisis. But anyway.. I got lucky because my '65 C60 already had an adapter plate from the factory-Chevrolet to big, round, truck bellhousing. So I just drilled new holes to match the Cadillac upper transmission bellhousing holes, the alignment pins lined up, and the crankshaft flywheel face to block height was the same enough that all I had to do was have the flywheel machined for Cadillac bolt pattern holes. I was even able to retain the original truck starter.

Even my mellow, near-stock Cadi engine build doubled the horsepower with about 200 lbs/ft more torque of the original 327.

You'll spend more than you think you should at first, but you won't have to spend it again for a long time because the Cadillac engines are reliable, durable, and happen to make excellent truck engines with their broad, flat torque curves at truck friendly RPM range.

All that aside however, a thorough refresh of the 350 with modern parts and a cam not designed soft for 1970s emissions requirements will wake it up pretty nicely, and it's certainly tough to argue with bolting the stock setup back in, in a weekend.

If it's just a work truck, wake up the 350 with modern parts. If you love the rig, then you can do better than an overhyped 454. If I were converting something today, I'd consider an LS before a 454. I mean, if I didn't already grok the Cadillac V8.

If you decide to go the 472/500 Cadillac route, here's a company that specializes in performance parts for those engines. They even sell complete built engines.

www.cad500parts.com

Tronman’s suggestion of the Caddy engine is an interesting one. You could look at the BOP 455’s as well. I have known of folks using the Buick or Olds in a Chevrolet vehicle.

I think the Olds swap is more straightforward as one can use the engine mounts for an Olds 350-based Diesel Adapting the tranny to the BOP pattern might be a PITA in a big truck.

I sort of assume this isn’t a truck that gets driven 10’s of thousands of miles in a short period. Finding your swap candidate nearby and just keeping it simple is probably the way to go.

That’s where the BBC, even with some short-comings, becomes the most practical candidate. Common as dirt. Going to make plenty of torque even if smog equipped and detuned.

There's also a 500+ cubic inch version of the Chevy big block available. I believe it was originally sold as a retro-fit for motorhomes that needed a bit more power to get the snowbirds back and forth from yankee land to Florida or Arizona in their land yachts.
Jerry

Can verify, Cad 500 parts house mentioned above are a solid outfit. They sell everything you could want to hop up a Cadillac V8. Also, you can use the motor mounts from a 77-79 425 and then the Cadillac block becomes coordinated corporate mount like an Olds, Buick, or Pontiac or Chevy V8.

My bus was a 327, yet it still had the factory adapter plate to the big round bellhousing. I've got a 13" clutch in the middle of its gigantic flywheel, too. I don't know if all '65 era C60s had that or not, but the additional include of a hydraulic clutch just really made my conversion job easy.. well, it would be easier to do again, after learning by doing all the expensive mistakes I did back then :-D

Also the Gen IV big block was available as a crate engine. It was a little better than the originals, which are generally long since picked clean in wrecking yards. I think it's up to Gen VI now, and you can buy a crate 502 from Summit racing, carb to pan, for $14,800. It makes 580lbs/ft of torque, which is very doable with a near-stock Cad 500 using a modern camshaft and light cylinder head port work, for half that.

After looking at the OP's photo of his truck, which appears to be an unrestored work truck, I don't believe he's interested in spending a boat load of money. JW 51's idea of a mild compression stroker kit (383 cu in) & a flat tappet RV cam would be a cost effective way to go, imo.

OTOH, old motorhomes with good running 454's are a dime a dozen, so to speak. Once the roofs start leaking on them, owners will practically give them away. The engines are truck engines with rotators for the valves & factory equipped oil coolers. Converting to a carb if neccesary is easy & fairly inexpensive. Only down side is getting rid of the MH after robbing all the needed parts off it.

I’ve looked into the RV engine option for another vehicle in my life. Cheap way to acquire a low mileage, big cube motor and tranny.

I do hear that disposing of the remains…is darn near impossible. And I’d have to do some mighty fast talking to get my wife on board with the idea of an RV carcass living on the property…for even a very short time.

Same deal with boats. Some desirable engines living in some terrible heaps of a boat. But then what do you do with the boat?

I hired my neighbor to help me get rid of my RV. We spent 4 days with sawazz’s & several trips to the landfill. Then a call to a scrap hauler. They were happy to take the chassis off my hands. Edit: The bellhousing, clutch, starter etc from the 350 will bolt right up to a 454. Just have to get the correct flywheel for whatever engine is used. If it’s a Gen V or VI, it’ll have the modern full circle rear main seal .

Cut them up with a sawzall and put them in the trash little by little each week. I did that with two different cars.