If a person had a good running stocker, not needing overhaul/boring, etc., no reason at all not to use it as is internally, with external improvements to intake/exhaust...maybe ignition. Rugged and ample torque. As I recall, the 302 I had years ago was rated (stock) about 300 ft lbs @ 1200rpm!! A 270 is not far behind. Ray
In my opinion, any engine that hauled a ready mix truck around, should be OK in a light car. I was a Motor Pool Mechanic in an earlier life. We had a herd of 302 GMC trucks. Never had much trouble with them. I mentioned running them at the lake and on the salt. I really liked them. As far as pistons, for the 302 head I never had any problem buying them from Aries. Or pins. Never had a bushing problem either. Granted we are talking 30 years + ago. Got one over 200 one way. Head gasket blew.
Anything could stand to breath better and they were not a high revving motor in stock trim. You don't have to build it like the Iocono dragster mill but it sure doesn't hurt it to wake it up a little bit. Wrist pin bushings are nothing to create if you have access to a lath and I haven't seen too many wrist pins actually worn out on a street only mill in my time. granted Rick has been at this at least 20 minutes longer then I have so maybe he as seen a few more then I have. LOL Aries probably still has pistons on the shelf because people are still storming the salt with these old mills. I don't know who the OP is having make his pistons but I know of a couple of companies that I have used for oddball stuff that has had a pretty quick turn around, well maybe reasonable is a better word.
Because America. Most of the old engines were very detuned. With a 270 or 302 we are talking about 120 or 135 HP stock. With a few simple tricks like dual carbs, dual exhaust, milled head, reground cam, and lightened flywheel you can pick up 25% - 40% more HP than stock, without spending a huge amount of money and without harming engine life and driveability. To me, this would be a very cool engine to have in a nostalgia type car or early style hot rod. If you want more HP than that, the cost goes up exponentially. If you want to double the HP you will have to spend way more than double the money, and you will be chancing a major blowup unless you spend even more $$$ on heavy duty components. To me if you really want that kind of hp you should forget the 60 year old sixes and get a late model V8 that has the power you want to begin with. To answer your question, you could rebuild it completely stock and it would last for 50 more years if you took care of it.
I went 177 with a mild 302 in my Vega. Single 4 bbl Holly. Mallory dist. As I remember it was less that 9:1 compression. Easy to start. Nice motor. Reason? Turbocharger. Junkyard Corvair turbo. Around 17 psi with water injection. All welded up with a torch in my garage. Like Beaner says, it is not a high rev motor. Joe Fontana made that Skinner head and his GMC/Studebaked went 200. But it commonly welded the flywheel and damper to the crank from vibration. He ran 7000 rpm to use those big ports. Had a cam with very big bumps. More than one way to skin cat. But I liked my way.
boost and low compression is cheap HP. With enough gears you don't need big revs to go fast. I don't remember who it was but someone said that with enough gears you could make a washing machine motor pull a freight train.
Beaner I have personally moved a fully loaded freight car 100 feet with a pry bar. It was about 10 feet long with a steel shoe at the end to go under the wheel of the car. By prying down 5 feet I could move the freight car about 1/2 inch. It took all morning. I'm sure I could rig up something out of a 1/4 HP motor that would have done the job in 1/2 the time.
I've been running a 302 as a daily driver in my '37 truck for five years now and it has about eighty thousand miles on it since fellow HAMBer, "Truckedup", built it and the truck. Venolia pistons 9.5:1, cam, chevy small block valves, 400 cfm carter afb, lumpy cam . . . probably about 230 hp and 300 ftlb torque. Hayes clutch, T5 tranny and chevy 3.36 rear end. I drive like an old lady but it will jump when I get frisky. Well, at least it did. Got it sidelined currently to replace the head gasket and do some cleanup while I got it apart. This pic was taken when I first got it and had about ten thousand miles on it.
Rich, do you have any recommendations for what damper to use? I was told a 292 one was OK for street use, but what if you want to run a little harder? Also would you chop the flywheel or run an aluminium one, or...?
Contrary to accepted knowledge, I ran a hub. No damper. If i was going to build a GMC now I would study up in the 12 Port News about a damper. BHJ is local and I would contact them to see if we could come up with something. They made the damper on my 26 Dodge Bros. Due to the SCTA rules I ran a steel billet flywheel. I like a heavy wheel around 35-40 pounds. I don't like winging a GMC. The crank is to flexibly and that is how they get broke or welded to the flywheel.
There's a long winded thread on the Inliners forum: http://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=61263 Either there is some mystical science involved in designing the correct damper, or everyone is over thinking it. I've had it suggested that a correctly rebuilt stock damper is as good as any. I've noticed that track roadsters like Hartman's or Spalding's cars ran no flywheel, just straight into an in/out box. I guess it must have worked for that type of racing where they needed to accelerate quickly. I managed to find a Chevy 4 bolt flywheel for a 10 3/4" clutch for my 270, I was told they're hard to find??
No, I think the dampers are identical. Best bet would be to figure out what year they changed from 4 to 6. My 270 is 1947 and it's 4 bolt, I think by mid 50's they were 6. Chevy probably changed around the same time. The clutch and flywheel that came on my 270 were quite heavy. A Chevy flywheel from about 1939 is the best for a 4 bolt crank. The one I found is from a Chevy truck, possibly a WW2 model or immediately post war, with a 10 3/4" clutch. Check Inliners International site for casting numbers. http://www.inliners.org/
The four bolt flywheels that I saw were very coarse pitch teeth. And used 6 volt starters.The six bolt flywheels I saw were a finer pitch, like maybe 168 tooth ring gear. The only four bolt engine I ever had also had the dampener made to accept a hand crank.
on the Chevy engines, the 6 volt setups had coarse teeth, the 12v setups had fine teeth. Probably something similar going on there.
All hydro ('52 up 248, 270, & 302) cranks are 6 bolt. '54 up for the rest. I've always used 235 - 261 Chev harmonic balancers simply because the engines went into Chevrolets & I wanted to use the Chev accessories. All the '54 & '55 248s I've run across have 6V ring gears, even the 2nd series '55s. In the early to mid '50s, a GMC could be ordered 6V or 12V, pos. or neg grd ...
The majority of 302s that I had hands on experience with were 24 volt with Hydromatics and painted green. The ones that I had here at home, only one came with a flywheel. It was a 4 bolt. Painted it orange.
My apologies to the OP if he feels the thread got high jacked. All in all good info,thanks to the vast knowledge of you guys thattook the time to respond.
Hey guys donyou know if all chevy 6s and gmcs had the same dipstick? I'm missing mine...the dipstick tube ends just above the valve cover not close to the block. Thanks
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