How big of an engine can I put in a 1979 Chevy C10 without major modification?

anything other than stock will require some modification.

what is heavy mods to you is nothing to someone else. my friend has a 502 bbc in a '68 camaro that originally had a sbc. modifications yes, but he does not consider them to be "heavy modifications".

what engine is in your C10 now?

With Chevy parts, you can put a Big Block, if your truck currently has a small block V8, you'll need front springs and beefier brakes, possibly a different transmission and rear end.

Change the intake to a carbed 1, use the distributor from a 75-86 chevy V8 (SBC or BBC all the same). Change the exhaust to accommodate the BBC headders. You may want to put in 3/4 ton springs on the front of your truck to hold the extra weight, or get BBC 1/2 ton springs from a 73-79 chevy C10 (The 454 was last an option in the half ton in 79). You may also want to rebuild your trans, or set the truck up to use a 700R4 auto trans to save 2 or 3 MPG. A larger radiator would help alot, you want to use a 6.2 diesel radiator, or a 454 radiator from a 3/4 or 1ton as they will all fit the same.

All of chevys gen 1 engines will bolt right in place and even hook up to all your stock parts if you have a v8 truck.

Thats the 262-400 small block design with any stroker thats built from those blocks

or the 348-502 big blocks and thier strokers

Now as power levels comes up you may have to change this or that.

In 79 c10 you have probbly a th-350 trans, maybe a th-400. In stock form the th-350 is good to about 400 HP with traction, the th-400 probbly 500 HP with traction.

A $500-600 rebuilt on those transmissions can bring them to the point of handling 1000 HP pretty easy

IMHO the 3 I would have on my list to pick from is

350 SB

383 SB stroker

454 BB

Chevys Biggest Engine

The largest that will bolt in is a 572 crate engine. You will need a good trans and rear end and a bigger radiator. A 502 would be a great set up.

A 350 crate motor should be sufficient power wise, but you can put a 454 in there.

454

heck, you can put 454, 502, it's what you want to go with and how much money you want to put in your truck it's up to you ,me 502 now that's me i'm from old school that' me .