i was thinkin on how to make a small block that would spin to hell and back 3 times over and this idea came to my head. take a 350 block, rods, and pistons, then use a 283 crank in it. that away u wouldnt lose so many cubes but still have the shorter stroke. im pretty sure that they have the same size main journals, and if they dont have the same size rod journals then u could use the 283 rods. what do ya think?

kolby

 

That would be considered a 302. They dont have the same size main journals. 350s are all large and 283s are all small.

 

Great idea. You're a good 35 years late coming up with it though. That is exactly what a 69 302 was. The only way to make it is with a 302 crank, or an aftermarket one. The 283 cranks don't have the same size mains as any 350 blocks. All 283s were small journals.

You can make the same thing out an early 327 block (same bore as a 350, 4.000") with a regular 283 crank, just like all the hot-rodders were doing before Chevrolet caught on when they wanted to enter this thing in the SCCA Trans Am series, and had to come up with a motor that made the 5 liter limit.

If you do this, you could use stock 5.7 rods and stock 302 pistons. A no-brainer.

 

i love this short (3") stroke=high rpms. if thats the case the 289 i have on a engine stand now ought to spin to 12,000 rpm easily based on it's short stroke and 4" bore.

 

I love it, too. My current 305 easily out-revs what the 327 block, 283 crank, LT-1 solid cam'd, angle plug 2.02/1.60 headed, single plane 302 I had in the mid-70's ever would turn.

If the key to revs is a short stroke, then explain those 540 CID big blocks reving to 9500...

 

seems like i saw in summit or somewhere that u could by a spacer type thing to make a small journal crank fit in a larger journal? might be dreaming tho.

kolby

 

Yeah, I saw that too... it was a donut type thingy with a matching main cap....very$$$$:lala: :lala:

 

Yeah there are spacer kits to do that.

 

Typically they're for 350 crank in a 400 block. I.E., still "large" journal crank, and definately not what you need for a "small" journal SBC crank in a 350 block.

 

Yeah, I haven't seen a small-journal to large-journal spacer kit since the late 70s... only large-journal to 400 ones.

 

yeah i tried a few years ago to buy one so i could use a 327 crank in a 4 bolt 350 block. no one has them after looking everywhere. most people don't remember the ones that were around in the 70s like rb said, all i got was stupid looks when i ask.

 

Its not just short stroke which makes an engine rev high. Its the ratio of stroke to bore. Since we all know a 302 is a good revving engine, if you exactly doubled the bore and stroke (not possible of course), you would have a 604 CI motor which revs exactly in the same manner as the 302. Other factors can affect redlines too, like an aluminium flywheel, or aluminium rods, lighter rotating assembly.

Sooner or later I want to de-stroke my engine to a 377 by putting a 350 crank in it. a 377 should rev to 7000-8000 rpm with no problem.

 

If you have the proper heads and cam to support it.

One thing I dont understand is that everyone thinks the 302 is a motor that spins 7000rpm no problem. If that's so, how come the 302's in Ford Trucks cant rev past 5000k?

 

shorter rods I think would be one reason


also isn´t there bore and stroke different

and a redline isn´t always the max the motor can take but sometiems a little above where the power just drop bad due to cam or heads

 

A F@#$ 302 is a 4 inch bore, so the stroke would be the same.

 

They have the same bore and stroke as the SBC. My point was the it was the cam and heads that determined a redline, not based on the stroke or some optimum ratio of bores and strokes.

 

IROC22 your on the money. VALVETRAIN determines RPM powerband! Not some small stroke! Friends got a 360 (3.48" Stroke, 4.060" Bore) Spinning to 11K!!! The trick is high rpm flow flow flow!! a Barry grant 950, 325CC Heads and a Tunnel Ram make that 11,000 Rpms possible, and this is a standard forged 350 crank, not some undersized bearing spaced 283 crank. Yeah, when you go that high you need strong $#!T of that there is no doubt.... he snapped the valves off at the face when the powerglide blew second gear and the engine over-revved to 15K!! it was making 850 horses on 118 octance alchohol mixed with nitro, and had total of 53* of timing.... do you know what a small block sounds like at 11K? I took my feet away from the floor board somwhere around 8,000! man its loud!

 

That puts you on coarse to building a 302 (I think) I'm sure guys with more knowledge will jump in. I have been thinking about building a 302 Z28 (kinda clone) if, for no other reason than to have it.

 

Hi Paul , Welcome to Third Gen . Org .

When replying to a thread , you may want to check the date of the last post . The thread you just bumped was last posted to in 2002 , making it a good 18 years dead .