Hello, New here and this will be my first build. 87 Iroc with the carbureted 305. Previous owner upgraded the fuel system and delivery to a Fitech 400hp system

I am currently pulling the 305 and have purchased a 350 SBC long block that was rebuilt 15-20 years ago and has sat on a shelf not touched at a large construction company since. It is a 4bolt that came out of a 77 1 ton truck. My plan is to remove the top end and only use the bottom end of this engine. I will purchase performance top end parts for the build and use the Fitech system that was on the 305. Is this a good plan to get to 400hp? Can I leave the bottom end of this engine as is and expect to get 400hp. Can I just bolt on the performance top end parts because this is a rebuilt engine or will I need to have any machine work done? What would you guys recommend for top end parts or kit to go with? Just looking for a weekend cruiser that I can do burnouts in and occasionally take to track days or road courses.

Thanks in advance

 

Gonna depend very heavily on what pistons are in it and what machine work has been done to the block. Can't very well predict what machine work it'll need of we don't know what it's already had, or how it was done: cylinders bored and crank ground "on the wear" instead of on the measurements for example, or whether the cyls were honed with a deck plate (not likely butt not impossible either, just, unknown). As well as, how many of The 70s Problems the block was born with and can never be set right, since 77 is right square in the middle of the worst years for all that: starter bolt holes drilled too far from the crank; lifter bores that don't point at cam lobes; bell housing dowel pins, and even head ones, in the wrong place; cylinder bores that aren't perpendicular to the crank, in the front-to-rear direction; oil passages that don't meet in the middle; the list just goes on and on.

 

Wow, sounds like the entire GM production line was having too many three martini lunches back then.

 

I think it was more of a don't-give-a-s*** attitude. Overall sloppiness in everything back then, especially machines that were counted on for accuracy butt weren't maintained or even checked regularly. Coupled with very poor quality control, as in, if engines or cars or whatever production unit are failing to meet specs and the scrap rate is too high, then just "adjust" the standards until the pass rate is acceptable. Of course the 1-yr 12,000 mile warranty in those days didn't help much either, since that let them ship garbage and by the time it failed it was somebody else's problem.

There's plenty of damn good reasons the 70s are referred to as the "malaise era".

 

I would take that entire engine apart
take the block to the machine shop to have inspected.
order a 383 rotating kit and some cheap aluminum heads.
A small 272 or 268 camshaft with a performer rpm intake
Bolt it all together and should be a reliable 425 hp

But an engine that has been 'rebuilt' and been sitting is never a good combo

 

thank you for this. I’ll have to lookup what a 383 rotating kit is.

 

Alternatively you could buy a 400 hp crate engine. https://vastrp.com/product/sbc-crate...gWZ_fWPQt7AgZE

It's not a hard number to get to either way.

 

It's crank, rods, & pistons, plus rings & bearings, that turn a .030" over 350 block into a 383. 350 stroke is 3.48"; increase it to 3.75", and bore the block out .030" (which has almost certainly already been done to that old truck turd, if not .060", in which case the block is now GARBAGE), it becomes a 383. Back in the day, we all used to do that with a stock 400 crank with the mains turned down to the 350 diameter, stock 400 rods, and stock 350 (or the appropriate overbore) pistons. Butt nowadays they make cranks with all the right dimensions to begin with, and purpose-built pistons that allow longer rods, which overcomes one of the weeeeeeeknesses of the stock 400, namely its shorter rods. And if you're tearing down a 350, and most especially if it turns out that it was built with crap rebuilder dished pistons like a truck mule most likely would have been, might as well increase the CID, and consequently the torque, by 10%, while you're at it.

 

The construction company probably had a fleet service with an engine remanufacturer. If they used ATK, there may be a tag or stamp on the engine. The rebuilt long blocks for a 1977 chevy 1 ton pickup are coded as VC09. I visited an ATK shop years ago when I was researching my engine swap project. It seemed like a good operation, but the reviews on Google are mixed. Fitech is a good start, but a trip to the machine shop would be prudent If you want 400 hp.

https://atkvege.com/fleet-accounts/

 

Like others have said, I would pull that motor apart and see what's in it and measure everything. After doing that, then evaluate what you are working with and decide if this short block is good for your needs, or to move on.