I am planning to swap out the stock 305 in the car. I am looking to produce anywhere from 330 to 350 HP. I am also looking at the most cost effective way to do this! Here are some questions:
*Can I stick with the 305, and rebuild it?
*Should I get a crate motor? I saw a GM 350 with 260 HP for a great price. What can I do to the top end of the motor to get more power out of it?
*Do I go the junkyard and get a 350 out of a car and rebuild that?
*Do I stick with the TPI or go carbed? I like the idea of carbed because I wont have an ECM!
*I know that LT1 or LS1 swaps are involved and that may be a future project, very far future!

Ideas, suggestions, Please help!

 

The 260 (or 290) horse GM engines are the "basic" 350, with low compression, small cam, and poor heads. Better cam with better heads will get the gross flywheel HP numbers you quote.

For a little more money, you can buy that HP out of the box with the 350 HO or ZZ4 crate engines. The HO requires a Vortec-type intake system, available either in carb or TPI versions.

TPI makes getting the higher HP #'s more difficult, but it will be emissions-legal, if that's an issue for you - carb will not. It also typically costs more money to get there. But, it will also be more economical down the road.

LT1 or LS1 gets you there in one step. You retain the emissions-legality and economy (if done correctly). It will probably cost you more than one of the crate setups, but used LT1's can be had for less than a new ZZ4.

Junkyard 350 rebuild is a possibility. Heads are the key, the typical factory 350 head is performance junk.

Rebuilding the 305 does not make any sense in any fashion. You may be able to get to 350 gross flywheel HP, but the same money spent to do that would get you 400 with a 350.

 

Wow, I guess the brakes it all down huh? I was thinking of going with that 260hp crate because of the price and figured i can get a cam and heads for it and still be under the price of the 330hp crates, or any rebuild. What does the stock 305 put out? I am assuming its not much and that the 260hp will give a big dif! But again, I want to be over the 320hp mark at least

 

Stock 305's were rated at 145 to 230 net flywheel horsepower from the factory. An '85 LB9 was rated at 215. "Net" means as-installed in the car, with induction system, air cleaner, exhaust, accessories (alternator, water pump), etc., functioning as they are in the car.

Those crate #'s are "gross" flywheel horsepower, meaning using a carb, velocity stack instead of air cleaner, long tube headers without mufflers, water flow and electricity supplied by the dyno facilities. Therefore, "gross" HP ratings will always be higher than the "net" HP ratings, and net is a much better indicator of how the engine will perform in the car. The difference is typically 15-25%; as various magazines have shown, for instance, by taking a 145 horse LG4 out of a car, putting a different carb & headers on it, electric water pump and no alternator and getting 180 HP out of it with no internal modifications.

The 305 I just took out of my car made around 250 rear wheel HP as calculated from dragstrip numbers. The gross flywheel HP would have been around 350, net probably around 300. That's a whole lot healthier of an engine than the 260 HP crate you're talking about. Compared to your (I assume) current LB9, the crate has worse heads, worse compression, and worse cam, but is rated with an induction that is more HP-friendly than TPI. The chance of it having more power with TPI on it than your current 305 is next to nil - the LB9 would probably be around 260-270 GFWHP.

If you want 320 HP, you're going to have to: #1 - figure out which "rating" system you're talking about; and #2 - justify that HP figure. So far, all I can tell is you pulled that number out of the air, perhaps because someone said that's what their engine produced and you want to match it. 320 gross flywheel HP isn't too hard to get, 320 rear wheel HP is a whole different ballgame.

 

I was in the same boat as you a few weeks ago. I was planning on keeping the tpi, and throwing a 350 in there, but decided it was cheaper and easier to go carbed. I bought a donor 1988 camaro, with a rebuilt carbed 5 speed 355. Just a thought but for the price of a crate engine, you can usually buy a low mileage performance motor, and add what you want. I went carb because of ease of tunning, and its my summer car. Plus to me, a hot rod should be carbed