looking at buying a 350 for engine swap from a guy i know. cant remember what year it is (70s ish). It's bored .060 over, has milled heads, a 502 cam, and 11.5 to 1 compression. here's the deal, I know with that high of compression, I can't run normal pump gas, and i'd really like this to be a streetable motor. i heard from a hot rod shop that a different cam alone should bring down the compression to a reasonable (10-10.5:1) range :confused: i'd really like to not have to get new heads for it, and i want to be able to run it off of pump gas. also, what cam would you guys recommend running? looking for around 400 hp, +/-. thanks guys. :usa:

camshafts dont affect compression ratio, but a smaller cam would definitly be more streetable. you might be able to lose some compression by getting thicker head gaskets..

i assume you meant that the cam has .502 lift, since a cam from a 502 big-block wouldnt fit too well in a small block. for a truck i would take a lot less lift if you want it to be streetable

Originally posted by drunkmarine
i assume you meant that the cam has .502 lift, since a cam from a 502 big-block wouldnt fit too well in a small block. for a truck i would take a lot less lift if you want it to be streetable

Yes if u get a different cam it would make a huge diference,

I suggest you pass on that motor unless you are getting a killer deal on it. Changing the cam and heads will get you where you can make it streetable, do you know how many cc's the heads are?. The cam wont affect your compression only changing heads or pistons. I dont think a thiker head gasket will drop the compression enough for what you are looking for.

Pass. If you are wanting to swap a motor into your Toy, find one that is a lot closer to stock. That buildup is totally ridiculous for a 4X4.

A long-duration cam CAN lower the EFFECTIVE compression ratio - at low rpm's. With more overlap and the valves open longer, more of the air-fuel charge is lost out the exhaust and back into the intake (reversion). This is the root cause for high-horsepower, high rpm cams costing you low-speed torque. Conversely at high rpm, these same factors combine with the sectional density of the charge in the runners to enhance scavenging and force MORE charge into the cylinders. Racers have exploited this "compression-lowering" effect for years; not only does a big cam make more high-rpm horsepower, it permits "cheating" in that a higher static compression ratio (than might be officially permitted by some sanctioning body) can be employed when building the engine than will be measured in a heads-on dynamic test - at starter motor speed or thereabouts. However, when you wind it up you'll still have that high compression, and if you try to get away with the big-cam effect to run that 11.5:1 engine on pump gas, you'll scatter it quickly.

So, while it is possible to lower the observed low-speed compression with a big cam, it's a really bad idea for what you want to do for several reasons. It won't allow you to run it on pump gas. It will suck - and I mean REALLY suck - below 2500-3000 rpm. If you're going to trailer it to the mud races with a tank full of alcohol, that's one thing. But from what you've said your purpose is, I agree with Black Dog and the others that said to pass on it. Also 0.060 over is a hell of a lot. Unless the block was sonic-tested by someone competent - and found to be unusually thick - I'd pass for that reason alone.

thanks for all the advice guys. i'm not going to buy it. a buddy of mine is thinking about it, though, he wants to swap it into his volvo :rasta: for a street racer. you guys think it'd be ok for that? :usa:

The max you can punch out a 350 is .060. This engine is on its last leg, so to speak. I would pass on it, unless its real cheap or free.
If you are putting this in a toy, you will have some serious problems trying to keep it cool, if you can at all.
Pumped up motors are not much use to a 4X4, of course that also depends on what kind of wheeling you are doing. For rock crawling. forget it, why do you need 400 HP, to creep along. Mudding, maybe. Logging trails, or the mall......:rolleyes:
I've wheeled with fourbangers straight 6's, and V-8's. And they all could do just about all terrain wheelin. Never needed big HP, just time behind the wheel, and learning the capabilites of the truck and yourself. :skull:

Originally posted by ranger
I've wheeled with fourbangers straight 6's, and V-8's. And they all could do just about all terrain wheelin. Never needed big HP, just time behind the wheel, and learning the capabilites of the truck and yourself. :skull:

I hear you on this one. my buddy's got a 350 in his Toy, mine does whatever his does, only more gracefully. I'm going V8 because a lot of the wheelin around here is mud, and because my motor is on its last legs and the cost of pumping up a 22R is comparable to putting a V8 in, so why not go more power? thanks for all the advice guys.:usa: