79 Chevy 250 Buildup Question

Hi, I recently got a 79 Camaro Berlinetta, with a 250 L6, I want to build it up to have like 300-350hp, (i plan on doing a comlete engine rebuild) the thing is though, i am horrible at matching parts for engines, I usually have my buddy do it for me, but he had no idea what parts to get for a L6, so could someone please tell me what combination of parts I would want to get like 300-350Hp , I've rebuilt several engines, and built up several more, the most recent one I built up was a Chevy 350 out of a 80's Camaro, I put that into a 88 Rx7 convertible, and i got about 340hp out of it (i could have done more, but i want the engine to last a god long time)

Thanks:
Tom H.


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I'd start with a 292 crank.

Bogie

Better start with a COMPLETE 292 "I"-6 to get near that horsepower. The biggest drawback is the cylinder head these engines have; specifically the siamesed intake ports. There are ways to improve upon this. You should also start with a 194 six cylinder head casting # 3864883; it has the smallest combustion chambers of the 194, 215, 230, 250, 292 engine family. It's going to take a lot of $ to do what you want, and even then, you probably won't make that kind of power. Time for a turbocharger!

Get Leo Santucci's book on hot-rodding the Chevy six. It has lots of good info for you.

So how much power could i get with out worrying about blowing up my engine, because as i said Ive mainly dealt with Chevy v8's, where you can get like 300-350Hp with out it blowing up, i may just end up going wth a 350 if it id going to be a pain in the butt and expensive, and as for a turbo, Ive thought about it, Ive got one laying around, and a buddy that works at a welding/machine shop to make me a intake manifold for it, its off of a 88 Rx7, i upgraded a na engine to a turbo one, then upgraded the turbo on it, it had WAAAAYYYYY to much boost and blew it up like 5 months later, I still have the car, but it now has the engine/tranny out of a 80's camaro (a 350 mated to a T-5)

The 250 block is weak in the corners and tends to crack out thru the head bolt holes. This is not conducive to holding back high compression ratios or blower pressures. This goes beyond O ringing the block and fixes like that, as these kinds of improvements only work when the foundation they're appied to is stable under pressure. Getting to 300 HP isn't all that hard to do with a 250, but keeping the block and head connected at number 1 and 6 is. The tall block 292 has more meat and is signifcantly stronger in these weak areas of the low block if you've just got to build a GM 6 this is a much better place to start sinking your money.

Bogie

Take a look over at www.inliners.org and search the forums. The 250 can give you close to the power you want with a great torque curve. Just finishing a 250 for my '63 Nova wagon and my desktop dyno program says 334 hp so I figure about 10% less .

What are the cam specs for this animal?

I'm using a CompCams 280 H and kit with an Offy 4bbl intake and an Edelbrock 600 cfm carb and cast headers. Cam tag says: RPM-Range: 1500-5000, Valve Lash: HYD.
Valve Timing: .006 Duration: 280
Lobe-Center Angle: 110 Duration 230@ .050" Lift:
Intake Centerline: Valve Lift: .538
Lobe Lift: .306

Are you going to use tube headers at some point in the future?

What are you doing for ignition?

The reason I ask is because at some point, I'd like to do a recreation of our old junkyard wrecker that I learned to drive in (had honest-to-gosh wood blocks on the pedals so I could reach- Dad had a bad non-union fractured hip for many years).

It had a Jimmy in it, but the builds are similar otherwise.

Using a GM HEI distributor with a new mallory pickup and Mallory coil, plan on just using cast headers. They last longer.

The biggest issue on the four corners is really Just the front two but mainly the right front one over the water Pump. And due to Over torqueing. Best thing to do is use studs.They put less stress on the block. I ran a 13-1 250 on the streets for over 12yr and I have never had a issue. I ran that Motor for 17 plus yrs. before rebuilding it. But if you want the cubes of the 292 USE
the 292 Not a 250 block with a 292. You can use a flat top custom piston and a 194 and have over 11-1 on the motor. The 250 block can use the 307 pistons. anything Other then a stock dished piston in a 292 is a custom ORDER.(meaning flat tops or Pop-up pistons) A flat top piston and a 230-250-292 head can get you into the 10-1 compression. The L6 heads With Stock valevs only flow about 170cfms If you do a Lump port to that same head with the stock 1.7 valve you can be looking at ruffly 200cfm. But if you install bigger valves the cfms can go into the 250 cfm range.With the right port work.