Could an 1976 302 bottom end withstand 10:1 high compression pistons, with stock rods and crank? (Performance heads, cam, intake, 150 shot, & etc. will also be added to the motor.)
It could but I wouldnt do it alot.At the very least put new fasteners on the rods and use studs on the mains.Make sure the oil system is up to parr as well.You might want to consider a little less compression too.The stock bottom ends dont do well above 6500 RPM with out witout good oil control.
I think alot of this depends on how hard you are going to run it. I would consider a main girdle and stronger crank / rods if I were planning to abuse it! otherwise this is not a combination that I would feel comfortable with for high RPM use. Dave
sure it could. maybe. might. but the next question i would ask is for how long? and do you want to chance ruining everything and starting again from scratch?
I'm kinda lost in what level I want to take my motor to, blower or high compression. I mean the car is still going to be my daily driver, and a weekend warrior every once in a while. My dad is telling to do 9:1 compression with cam, heads, intake, headers, and a 150 shot.
Save your money.Just do basic stuff that will allow you to upgrade later when you have the cash to really throw at it.You know,better cam,intake,carb,headers,exhaust.Save the laughing gas for the when you have the Good reciprocating assembly money.Nitrous on something not built for it WILL eventually make for a 350 pound cast iron grenade.
Heck yeah it'll handle it. 302's are a heck of a lot stronger than people give them credit for. You'll bust the block before you ever break a crank or rod (usually....) Oh wait I see that there is Nitrous in the mix.....it'll last...a little while. How long is dependent on how heavy your right foot is and how quick you can grab the next gear.
That 150 shot of NO2 is going to cause problems with stock rod bolts and pistons. Your dad is probably closer to being right than you are. You are driving along and get a wild hair up your - - - - and mash the pedal to the floor. your engine is producing as much power as it can and then you push the magic button. SLAM! 150 extra HP is pounding at the pistons, rods, bearings and crank. Temperatures go up and pressure goes higher than the block was made to handle. The tires will break loose and your engine will over rev. Sideways into a pole or an engine that screams past its ability to hold together. The end. It doesn't always happen that way but it could any time you don't have your head on straight. I have seen the split blocks, pistons with holes in them and rods that look like sombody took a 20 pound sledge to them. The engine, properly prepared, can handle it in small doses occasionally but can you handle it? Are you ready to ignore the power most of the time? Are you ready to NOT show it off?
10:1 is not high compression N/A, and with good squish height and/or aluminum heads it's easy to do. With nitrous you might want to drop the compression to around 9:1. The stock bottom end is fine for this with the exception of the 5/16" Ford rod bolts. I would at least have some ARPs installed. Nowadays for not much more than what a machine shop charges to replace the rod bolts and true the big ends you can buy aftermarket rods that already have 3/8" ARP bolts installed. I ran a 125-150 shot on a 9:1 302 with cast pistons for about 13 years. A good nitrous controller makes it possible.
The worst part about nitrous is having to refill the bottle all the time at $40 a pop for a 10 lb bottle. Me, I would keep the 10:1 motor N/A with a good set of heads, cam, intake and exhaust and just have fun with it.
Stock 302 rods/cranks are pretty good.I'm with mavman,just have the rods checked & use some arp rod bolts.With a girdle and good pistons I've seen many a "stock"(block/rods/crank/maincaps)302 live up to around 500 hp,N/A or sprayed/boosted.Anything over that & you'll be splitting the block in two eventually.My STOCK(of course it had factory TRW forged pistons)roller 302 held up to bunches of 150 hp NOS hits for years w/ no more than ARP rod bolts and ARP head studs.Motor never saw over 5500 on bottle/6200 N/A though.
I'm pretty sure you would have to set your ring gaps a little wider too if you are gonna go with anything other than N/A. Correct me if I'm wrong on this. I'm building a 331 right now and it's the same dilemma I have, if I go with supercharger or nitrous I need to set my gaps higher but I'll burn more oil I was told.
here is a thread that could go on forever... I agree with most of you, arp bolts everywhere, and 10:1 is not to high.. I would build it with 10:1 and set up the spray with just a 75-100 shot (thats alot of extra juice) with a good controler and revlimiter.. I would say that with mild abuse you could run that set up for several years with no issues.. Me, im going to twin turbos on a stout 306 and a 100 shot of giggle juice... Coming next spring..
why not a supercharger instead of the nitrous oxide? that might be a little safer, probably more $$$ though
