502 block with 396/427 crank? [Archive] - Chevelle Tech

: 502 block with 396/427 crank?


Pvt.Cowboy
Dec 31st, 04, 6:27 PM
I'm wondering if this may be a good high-rpm foundation for a turbo and Accel fuel injection.

It sounds absurd, I suppose, but can anyone tell me what this formula would create in displacement and what behavior characteristics it might have? I'm coming up with a kooky result from a displacement calculator based upon the info I've found: 471 CID. Maybe this combo doesn't even work, since I've never heard anyone mention it here.

What would be the right rotating assembly combo for pump gas compression?

Wolfplace
Dec 31st, 04, 8:06 PM
Originally posted by Pvt.Cowboy:
I'm wondering if this may be a good high-rpm foundation for a turbo and Accel fuel injection.

It sounds absurd, I suppose, but can anyone tell me what this formula would create in displacement and what behavior characteristics it might have? I'm coming up with a kooky result from a displacement calculator based upon the info I've found: 471 CID. Maybe this combo doesn't even work, since I've never heard anyone mention it here.

What would be the right rotating assembly combo for pump gas compression? =

You got the displacement close, it's 472.
The stroke is 3.76 not 3.75.
It would make a very good hi revving big bore 427 & almost all the newer heads like the big bore a lot.
The turbo compression should be about 8.5 so you would need pistons to get you there with your choice of heads.

As for turbos & FI someone else will need to address that as my knowledge FI would probably not fill a thimble :D

sobever066
Dec 31st, 04, 9:24 PM
Wolfplace have you built any de-stroked 502's? I was looking into doing this for my next engine build. Big bore and short stroke. Thanks.

Wolfplace
Dec 31st, 04, 9:51 PM
Originally posted by sobever066:
Wolfplace have you built any de-stroked 502's? I was looking into doing this for my next engine build. Big bore and short stroke. Thanks. No but it is intriguing if you want a hi RPM deal huh :D
Kind of like 377's.
I am not a fan of taking inches out of a street deal in most applications as cubic inches are power in almost all normally aspirated stuff smile.gif

You can make about the same HP with the smaller engines,, but for a barge there is nothing like torque,,,,
Just spent the afternoon playin on the dyno with a mild 489 torque type engine that is supposed to end up in a magazine eventually & this thing, with no tunning & very rich (like 10.5 to 11.5 AFR ) never went under 500 lbs ft from 2800 to 5500 where we stopped the test & idled at over 15" at 850RPM
This is not "special corrected magazine numbers" either ;)

jakeshoe
Jan 1st, 05, 1:17 AM
Mike,
Tell us more about that motor...

My 505 shoulda been close to that with the mild solid roller....

jakeshoe
Jan 1st, 05, 1:19 AM
Pvt. Cowboy,
That combo can be done...

You can use an old 427 steel 2 piece crank with an adapter, or use a newer GM forged one piece crank from a '91-newer 427 truck motor. I can look up the part number if you get serious.

I think it would be a good street deal, kill some of the torque, but have the inches, and the bore to really scream up top.

I would build it for a minimum of 7000 rpm...

pdq67
Jan 1st, 05, 2:16 AM
500" Pro-Stock motors are like 4.70"b x 3.60"s and put together to run upwards to 10,000 rpm AND above!!

They used to do the same thing years ago with 427's by installing 3.25" and 3.50" 348 and 409 "W" motor cranks by making them fit the BB..

375" to 400"+ motors would run waaaay up there!! Just like the little-bitty 302, Z- motor!!

pdq67

GRN69CHV
Jan 1st, 05, 7:30 AM
If you think about it, a healthy 472CI Chevy big block whether by bigger bore or shorter stroke is still potent. You are only talking .120 difference in leverage (6%) between the 1.88" centerline of a 427 crank and the 2" centerline of a 454/502 crank. A 475CI short stroke motor is still going to put out 500+ ftlbs torque. The biggest hurdle will be getting pistons.

Busted Knuckles
Jan 1st, 05, 12:23 PM
Pvt Cowboy, I have a late model 1-piece rear main 3.766 crank with the screwball balancer than they use, very low mileage, still std/std. Email me at 81vette4speed@cox.net and I'll make you a deal on it.

Wolfplace
Jan 1st, 05, 2:59 PM
Originally posted by GRN69CHV:
If you think about it, a healthy 472CI Chevy big block whether by bigger bore or shorter stroke is still potent. You are only talking .120 difference in leverage (6%) between the 1.88" centerline of a 427 crank and the 2" centerline of a 454/502 crank. A 475CI short stroke motor is still going to put out 500+ ftlbs torque. The biggest hurdle will be getting pistons. =
Not a problem, any standard 1.520 c/h piston is a "bolt in" with a 6.385 rod for one simple combo

Another is the 6.535 rod/ 1.395 piston which will put you .010 out of the hole in an undecked block.
All standard stuff & easy to get in different configurations smile.gif

jakeshoe
Jan 1st, 05, 3:43 PM
Mike,
Tell us about the 489...

Wolfplace
Jan 1st, 05, 5:43 PM
Originally posted by jakeshoe:
Mike,
Tell us about the 489... =

Originally posted by jakeshoe:
Mike,
Tell us more about that motor...

My 505 shoulda been close to that with the mild solid roller.... =
Hi Jake,
Sorry about that I started to answer last night & got distracted,,,

Pretty simple basic bolt together deal, 489, Ede 60459 roval heads, Ede 5062 cam .527/.553, 224/232, 114 lsa, 109 icl. I believe it's called the Torker Plus, RPM intake, 1413 800cfm Ede carb, Probe rotating assembly.
Carb was great at part throttle like hi 13's, low 14's & pig rich under power like 10.5 - 11.4 (AFR)
Timing was 36 degrees, 10.8 compression
numbers were:
2800 - 267 - 501
3000 - 306 - 519
3500 - 359 - 538
4000 - 427 - 547
4500 - 460 - 538
5000 - 480 - 514
5500 - 478 - 456

The compression was higher than planned but the parts were as supplied & I just supplied the machine work & dyno time along with profiling the cam & flowing the heads etc.
Cam was advertised as 302/304 but measured a surprising 285/288 at .006. The rest of the numbers were right on.

Heads were 315 on the good "port" & 307 on the "bad" port. Heres the 'bad" port, I don't have the "good" one in front of me.
050 - 38/ 31
.100 - 74/ 64
.200 - 146/119
.300 - 218/150
.400 - 260/179
.500 - 291/207
.600 - 307/229
.700 - 302/245

The sick part was using an original 512, H29 date coded 4 bolt 427 block for this :(

jakeshoe
Jan 1st, 05, 10:55 PM
Hmm...

Pretty healthy for the very tame flat tappet cam.

I was estimating (EA 3.0) a smidge over 500 "real" HP, and ~550-560 lb/ft for mine...

So in actuality it may be more than that.

Actually the 505 will live again soon, I am just not putting it in the Chevelle. It apparently wasn't destined to be in my car after all the fits it gave me last time.

I'm not much of a believer in stuff being jinxed, but that project just was from the moment I started dropping it in the car.

505 4.350 x 4.250
6.135 rods
SRP flattops.
242/248@ .050 Solid Roller, Crower SD lifters HIPPO.
10.2 comp.
390 casting closed chamber ovals fully ported with 2.19/1.88 valves.
RPM Airgap
Holley 830 annular carb
etc.

I'm looking for a roller to put it in eventually.

It is sitting in the garage floor, fresh sleeve, 2 fresh pistons, in need of assembly.

I'll get around to it one of these days, no hurry since it has no home to go into.

The tame 427 has been breaking enough stuff on street tires lately to keep me busy.