Would like advice/info on engine swap

[Connor C]

Hi, I currently have a 92 c1500 with a 305 TBI, 700r4 combination. The 305 is feeling pretty weak and i've been researching new engines. I thought about rebuilding the 305 but id rather drive the truck up until a new engine is ready and it just doesn't seem worth it in the long run and resale value. I want to move up to a 350 or possibly bigger according to budget. I started out looking through Kijiji ads for engines to rebuild. I liked the idea of taking my time, picking out parts and putting it together but understand it will get expensive really fast. I was convinced by someone else to go crate engine, which to me seems kinda boring but more economical. I live in Canada and I've found it pretty difficult to find dealers for crate engines. I was looking at the GMPP 350/290 base long block which costs around $4,000 CDN at a couple GM dealers or other performance parts stores. I know Jegs and Summit sell them and they look like a great price on their site but by the time shipping and conversion and border fees it becomes ridiculous at over $5,000. I can't get by the price even at $4,000, it seems so expensive for what it is with the low flow/compression heads, but maybe thats just me not fully understanding the costs of the different routes. I'm not looking to make 500+ horsepower but I would want more than the 290hp which I think is without accessories and at the flywheel anyway but I might be wrong. I kinda planned and roughly priced out doing the 350/290 route and would probably swap the cam which then sends the warranty right out the window, so I was wondering if anyone has gone the 350/290 route and what you did to it or if anyone has any other suggestions. I'm open to different ideas like possibly 383, 327 or 400 but I feel like if i'm having a hard time with the price of a 350 the others are probably way out of my price range. I have no interest in an LS swap or full drop in turn key ready crate engines. I plan on keeping the TBI and converting to 350 compatible parts like the injectors, chip, knock sensor and so on. I like the reliability of it and have convinced myself to stick with it aside from going carb. I'm also not in a huge rush any more especially with Covid-19 making its rounds I might end up setting this back to next spring, so I could possibly spend the next year collecting parts.

Any advice is welcome,
Thanks.

 

[Schurkey]

The 290 hp 350 crate engine will be a poor choice. You'll need a different (expensive!) intake manifold, and a different flywheel/flexplate. You'll give up being able to use a roller cam.

Find a 1996-up Vortec 350 short- or long-block; or a 1991-ish CAPRICE TBI 350. I had a service-replacement "Crate" engine from a Caprice/Roadmaster/Caddy in my '88 for about eighteen years. It's a direct drop-in except that the oil pan needed a plug for the low-oil-level sensor hole. Has a slight bump in compression, and a roller-lifter valvetrain. After 18-something years, the head gasket popped. I put in a rebuilt Vortec short-block with aftermarket aluminum heads, a carb-style intake, and a TBI adapter and the OEM TBI unit. The hard part was making the EGR work, and making the coolant bypass at the water pump gasket area work. Depending on your selection of core engines, a USED Vortec 350 could be a contender; although probably with different heads or a really-expensive intake manifold.

You'll want the 350-sized injectors; and a 350 PROM or custom tune.

Other folks will have to advise you on 383/400 cid options. Remember that a more-powerful engine will require upgrades to the trans and rear axle. The 8.5" rear axle is a weak point already; particularly the leading-trailing brakes.

 

[Connor C]

Thanks for the reply, I forgot to mention that I have 2 intakes that are laying around that work with the 350/290 since they are pre 87 heads. I know if I go vortec i would have to get a new intake that fit vortec heads which cost around 500 if I remember obviously I could look around for better price. It's not a deal breaker just thought I would use one of the intakes I already have, I know they aren't the greatest but one is an aluminum unit of an 80s corvette and from my research it seemed pretty decent. Where abouts did you get your rebuilt vortec from? was it from classifieds or online? I like the idea of the vortecs, but I would just have to add an intake to my cost is all. I definitely think 383 or 400 is out of the picture my trans will need to be rebuilt i'm guessing but i'm not after that kind of power.

 

[Schurkey]

I bought a Vortec 5.7L short-block at a "treasure yard" for about $200, pulled it apart, cleaned it up, replaced rod and cam bearings, rings, and gaskets/seals. It needed one cylinder bored .030 due to a rust line in the cylinder wall. It had sat with no heads in a barn at the Treasure Yard, that cylinder must have had some water in it. So I bought one piston. Other 7 cylinders got a dingle-berry hone and re-used pistons 'cause the cylinder taper was only about a thousandth and a half.

This is the beauty of buying a "used" engine from a modern, fuel-injected, overdrive transmission-ed vehicle: They can have a hundred and fifty thousand miles on them, and still be wonderful inside.

I re-used the crank, rods, 7 pistons, the oil pump, the block, the main bearings, and the oil pan. I did put a higher-pressure relief spring in the oil pump.

Damper, water pump, timing set, and timing cover came from the engine I was replacing--the Caprice crate engine. The timing cover and water pump needed some rework to the Vortec block. The front accessory drive was original to the truck.

A machine shop cut the decks .025; bored and honed one hole, and matched the aftermarket flexplate to an OEM flexplate for balance. I didn't trust the aftermarket flexplate balance weight. It looked "wrong". Turns out it was WAY out-of-balance. I did everything else.

 

[Erik the Awful]

I rebuilt my own motor. If I had to do it again, I'd buy a crate motor. I might have saved a couple hundred dollars, but spent too much time for the price.

 

[Connor C]

Thanks for the reply Erik, I've heard that quite a bit. Do you have an insight on the 350/290? It seems like everything I read is it's either a fantastic engine or thats it's just awful, not much inbetween.

 

[Erik the Awful]

No insight at all. I can tell you the specs on all the engines I've built, but I've never bought a crate engine. The takeaway I've had from others is to buy from a reputable rebuilder. I wouldn't hesitate to buy from GM or Blueprint Engines. Scroggin-Dickey sells ATK engines, so I would trust them as well.