A friend of a friend is putting a 418 stroker into his late 80's vette. That seems like a very odd size to me and I have not had a chance to talk to the guy to see what he started out with. How is a 418 stroker possible? What block do you start out with? 418 stroker just sounds wierd...probably because I have never heard of one.

 

There are plenty of ways to come up with different displacements by playing with the bore and stroke.

If you maintain a standard 4 inch bore, you have to have a 4.15 inch stroke to get close to a 418. I don't think that is possible. SO, you have to look at some other combinations.

I don't know what a typical big block bore is, but with 4.5 inch pistons it would only take a 3.275 stroke. Many ways to get many things done. Ever hear of a 377? People make them.

 

I vaugly remember hearing of a 377 stroker a couple times, but what pops into my head when I hear "stroker" would have to be a 383 or 496 to a lesser extent.

 

Most likely it's a 400 based small block... We've built a lot of strokers from this platform, the most common being 420 and 434's. What your friend probably has is a 400 bored .020" over to a 4.145" bore with a 3.875" (3 7/8) stroke crankshaft which would come up to about 418.2 cubic inches... If he is using a standard bore block (ie., a 350 based block with a 4" bore) he is probably running a 4" or 4.020 bore and a 4.125" stroke (which is a MAJOR PITA!!!); so I'm betting he's probably running the first combo. FWIW: We're nearing completion of a HUGE small block...468 cubic inches (yeah...big block territory). It's a GMPP Rocket block with 4.185" bores and a HUGE 4.250" arm...
-Jeb Burnett

 

How 'bout my crazy combination, .030 400 block with an off-set ground 400 crank ground to 3.825 to give 414.91.

Jake

 

You're weird, though Jake...
-Jeb Burnett

 

Don't such long strokes grealy limit RPM potential?

 

Well, that depends on what you mean by "greatly limit".

You've got to remember that big blocks have much longer strokes right from the factory. Only the 396 and 427 BB had 3.75 strokes (oh, yea, there are a couple of really odd BBs that didn't get made for very long, forgot about those).

The 454s and up all have longer strokes than mine. The 434 SB I'm building now has a 4" stroke too.
I built a 2 bolt BB, 468 years ago and it ran mid 8's in the quarter. Guy (lead footed Skip) use to bring it back from some meets with 9200 on the MSD tell-tale. I told him it wasn't gonna live up there, and I was right.

You should have seen the underside mounting surface of the main caps when I did the autospy.

Jake




[Modified by JAKE, 5:21 PM 4/2/2002]

 

dupe


[Modified by JAKE, 5:27 PM 4/2/2002]

 

The long arm can certainly limit RPM potential... But, if the motor is built with excellent lightweight internals, a stroker can turn some pretty impressive RPM's. Witness my little 396" sbc stroker...All forged lightweight reciprocating assembly: Callies Racemaster crank, Oliver billet connecting rods, and JE pistons, all internally balanced with a buttload of mallory... It busts the 7000 barrier like crackhorse looking for a rock!!!
-Jeb Burnett

 

My friend's 396 in his 95 Z-28 sounds a lot like your setup. Some kind of top notch callies crank, oliver rods, SRP pistons. Too bad his doesn't run. More :bs than you could possibly imagine happens to this guy.

 

Your valve train and camshaft selection(hydraulic vs. mechanical) greatly affects rpm potential as well.

 

Long strokes limit RPM potential because the piston is moving up and down in the bore so fast, that it doesn't give the cylinder much time to fill with air.

I know this why???

I read it in Hot Rod today, and it just happened to stick out.

JMR

 

Could it be an LS1 stroker? They are making anywhere from 418 to 422's plus the 427 stroker packages out of the LS1's.

 

Long strokes limit maximum RPM - as compared to shorter strokes - primarily because of piston speed and the resultant stresses.

You can opt for lighter pistons and still rev the he** out of a long stroke engine with no detrimental effects.

For example, the BBs I use to build with one carb - back before everyone was climbing on the 500/600+ CID band wagon - were all 4" stroke engines and they all were regulary taken to 8200/8400 on each pass and we never broke an engine that could be related to the stoke. None of that internally balanced stuff either; no Hi-Tech, just anvil reliable.

Sure valve train stuff would die - since it's the real weak link anyway - but never a problem that could be attributed to the stroke length. These engines all used stock GM rods too, 6.135" with 7/16th bolts, not any of the high dollar stuff like Carillos. Forged cranks and four bolt mains were standard fare.

Early BB aluminum heads were notorious for the studs moving around and we'd occasionally break off a stud boss - longer studs cured this. Valve springs would lose pressure and we'd break a K-Motion now and again, but the leakdown and bearings always looked great with only the amount of wear you'd expect from a engine pulling you to 150/170 MPH in a quarter mile week after week. I'd only have to do once a year re-freshening at the beginning of the season, so I'd say they performed as expected.

Unless you have plans on going higher than 8200/8400, I wouldn't be concerned about a 4" stroke engine. As long as the clearances are right, the balance is "on" and the A/F ratio is correct - pedal to the metal and hang on.

Jake

 

Jake, can you send me a list of what you have put your engine together with? Like what type of crank and by who and estimated $$$. I want to end up doing a 400+ cid small block pumping around 600 hp and 600 lb ft.

 

Well since my I have a daughter who's a freshman at Harvard, I don't have the $$ to throw around like some other folks I could name (envy, envy), so I had to save $ wherever I could.

I sent you an email with all the parts I used. Let me know if you need any more info.

Jake