350 rebuild

wanting more power out of my 350. some companies have performance top end rebuild kits that put out 420 hp. Wouold a person have to change out pistons and crankshaft among other things to get more hp out of a standard 350?

If your engine doesn't have excessive wear, you can add street power by changing the camshaft/lifters, intake, carb, cylinder heads etc. You need to do your homework though - if you don't match the parts and their powerbands, you can wind up with a dog that doesn't go fast, but hey at least it sounds cool at idle!

Also beware. Most of those "bolt on" kits have a compromise in them somewhere. That is, there are better overall combinations by using various componenets from different sources. One example is the Edelbrock "Performer RPM" kit. The heads and intake are excellent. The cam is an antique and the carb is a paper weight.

What year of 350 and what vehicle was it originally installed in? Some 350s are better than others. Need this information to answer the second part of your question.

Jim

The 1988 to 1995 350 blocks are better than the older ones,have the better main seals.Did this to a customer's 1981 Chevy truck.Instead of using the old block,used a 1988 to 1995 350 block.Check for any scored cylinders,the block might be junk and machine work needs to be done to the block.

Also beware. Most of those "bolt on" kits have a compromise in them somewhere. That is, there are better overall combinations by using various componenets from different sources. One example is the Edelbrock "Performer RPM" kit. The heads and intake are excellent. The cam is an antique and the carb is a paper weight.

What year of 350 and what vehicle was it originally installed in? Some 350s are better than others. Need this information to answer the second part of your question.

Jim


Jim, The 350 as per block information is from a 74 impala, nova, camero I have the engine in my 64 chevy shortbed fleetside

more than likely your 350 has crappy dog dish pistons that really hurt compression. if you are only going for 420 horsepower, the crank and rods should be able to take that for short bursts, though a longer time at peak horsepower would cause a problem. another issue is how many rpm you would have to turn to get 420 horse in a 350. i would guess at least 6k rpm, so the stock bottom end could be alright, again only for short bursts. i would still change out the pistons to some with less of a dish in them or get heads with smaller combustion chambers to compensate for the stock pistons. if you replace the pistons, might as well do the whole bottom end. and i would either way use an oil pan with a built-in windage tray

for that much horsepower you should replace them, but if your goin to do that you should bore and stroke it too along with cam, intake and carb

30 years ago, some bracket racers used to get junkyard motors for $250, pull the pan and check the bearings, and if everything looked good, they would throw a cam, intake, carb and headers on and go racing.

and a lot of those motors ran well for a long time. even with cast pistons, cranks, and 2-bolt mains. a lot of those cars were running 11's and 12's with a single 4bbl, no NOS or turbos like you see today. blowing a junkyard motor is not as bad as blowing a $5,000 race motor.

of course a race car is lighter, has better suspension, and a high stall convertor (if you are running a slushbox). all that contributes to performance as well.

whenever you add power, think of the "weak-link" theory. added power causes added strain - everywhere.

add power, and now rear ends, transmissions, convertors, clutches, etc. are all under more strain. same for driveshafts, axles, motor mounts, crossmember mounts, etc. and a more powerful motor from a top half kit will put more strain on the lower end bearings, rods, pistons, block, and crank. it will increase frame flexing under power as well.

if you just want to fry the tires or jump on it now and then on the street, you'll probably be ok with engine mods and a higher stall torque convertor. but if you want to race with slicks or street tires that really hook up, you might want to re-examine your overall goals for the project as far as the total package goes.

350-375 hp at the rear wheels is more than enough power to hose stock rear ends and trannys, even though that seems tame compared to a lot of cars these days. if you look at real high HP cars on the street today , most of them will have beefed up suspension and transmission components.

me personally, i prefer to build the chassis up first (even with a slug motor) and add power to the project last. when you break rear ends at the racetrack and have to be towed home 40 miles, you learn to think about that stuff first on your next project. :bigthumb:

good luck!!!