ajrothm

Searching around for crate and built motors, this keeps popping up in my mind. To get 500 crank hp out of a 383, it seems that its going to have to be a pretty radical motor with a correct combination of parts to get the power. Why not just buy a ZZ502? Its carb to pan for $7500. Its got a forged bottom end and the cam and compression ratio is pretty mild, not to mention a warranty from GM. To get a 383 that makes that kind of power is going to cost the same amount of cash, if not more once dyno tuned and I would guess not be as streetable or have as much longetivity.

Down side to the 502 is it weighs 250-300lbs more then a small block, the small block accessories won't fit and it would probably have overheating problems in a C3. Also you would have no option other then an L88 hood.

I would still think a 502 is easy mid 11s in an auto C3 and you don't have to worry if some crate motor company building these high dollar motors in their backyards are going to stand behind them.

Food for thought.

itsonlyairandfuel

No replacement for displacement.

Corey_68

502 > 383 ANYDAY of the week...

billlambeer

If you dont have to use a small block, go with the 502, i would anyday of the week, GM performance also makes a 383 crate that outs i think its 450 horse, which would be somewhat close and come with the warranty, just food for thought, if you do need a small block.

MonzaRedConvert

Have you considered a bigger small block? Maybe a 406 or a 434? I think you could get the horsepower numbers you are looking for without the added weight and problems with hood clearance, cooling, etc.

miechesa

I'm still deciding on small vs big block, Got the motor out of my 74. A 500 hp 383 will probally not have enough vacuum to run brakes either. Having to decide weight,horsepower, reliability,gas prices(going to be daily driver),Installation,price.I'm leaning toward a midly built 454.

ajrothm

Well I don't really care THAT much about the handling detractions from the additional weight. I am just thinking a mild(comparatively to a 500hp 383) 502 would last longer, be less temperamental and still leave room for future upgrades if needed. My issue with converting to a big block is a I don't want to alter the car's wiring, or accessories. I don't want to lose the AC. I could always buy a different PS pump but all of my AC brackets I don't think would work. Aside from the potential over heating issues with the 502, I think it would be more streetable. Lower compression, smaller cam and tons of tq would work well with a high way gear, mild 2500-3k stall converter. At the point where I am at, I will have to buy everything anyway, starter, headers, carb, water pump etc so... Its almost cheaper to go with the 502 then the 383. But the 383 will fit better, use all stock accessories and one important thing, allow me to use the stock SB hood.

Anyone actually dyno a 502 yet?? rwhp?

We built an LS6 big block for my dad's 59' and it was an absolute nightmare for 5 yrs trying to get it to not over heat... We tried EVERYTHING including building a low compression, small cammed 454 truck motor and it would also over heat, even going down the road at 50mph. We stuck a ZZ4 in it and it runs 180* all day long. I don't want over heating issues and it seems that is an association with vettes, especially with AC.

Any 502 owners feel free to chime in...

MELVIN

I have a the 502/502 long block. I placed a e brock perf EFI system on it

This engine is very streetable/very reliable. I have taken many 8hr one way trips with no cooling or mechanical issues

The best RWHP, dynod that I could get, was 478 rwhp. But remember, that was specifically tuned the best I could get (mixture, timing, fuel air, etc), open headers, and it took a long time to get it figured right. That parameter is saved in my e brock memory, along with a "economy" setting (highway), and around town

I have my own opinion on strokers: Strokers have to work harder on everything that they do. Longer stroke is harder wear on parts.

This motor actually runs cooler than my OEM 427. And Im using the original 427 copper radiator

Glensgages

You have a recent born-on date (May 2006 ), so I'll repeat this story for you and other recent-additions to our Forum.....

A former Forum-member had rubber-bumpered Shark, with a healthy (big heads & cam, decent squeeze, etc. ) high-RPM 468" rat-motor in-front of a 4-speed, 4.11 gears, and slicks that ran at my local strip:
I believe his best E.T. was 12.11 @ 116 MPH.....

I was at the strip for Opening Day a few years ago, and saw him in the staging lanes, then watched him rip-off a 12.14 @ 116 run:
a few pairing later was another mid-'70s Corvette that idled into the water-box, did a modest burnout, staged, 'walked' off the line and then stopped the clocks at 12.03 @ 112 MPH.....


Walking thru the pits between runs, I spied that car, walked-over to it, and introduced myself to the owner as he tinkered under the hood:
after seeing the relatively flat valve-covers, I asked if that was a ZZ502, and he replied it was, so I asked him about it, and the car, in-general.....

Bone-stock ZZ502, headers and side-pipes that were 'laying-around' (his-words ), an 'on-sale' 10" converter and a 'used' THM400, 3.90 gears and 29" x 11" M&H slicks, that he had towed to the track (between living 50 miles away, and the slicks, he thought it best to use his roll-back that day ):
he admitted he'd been 'gentle' on the first pass, and would be more aggressive on Run #2.

For the 2nd run, he boiled the slicks, staged 'on-the-converter', and promptly sent pieces from the IRS all-over the starting-line:
I helped him push it off the track, and he went for his roll-back to bring to the car, so I 'looked-over' his set-up, and it was nuthin'-fancy, indeed, with his shift-light set at a lazy 5400 RPM.

Once we the car was on the roll-back, he jacked-up the rear of the car, and asked me to start the car, and put it in-gear, to 'see-what-is-spinning' :
it idled at 800 RPM, and I detected no race-gas fumes from the exhaust.....

ajrothm

Interesting story for sure...sux it blew.. I would have been interested to see what it would do ***** out. 112mph is not that good for the HP. Lots of variables affect the mph though. 115-116mph is a average mph for a street car, especially if it leaves good(auto w/stall).

My 99TA goes 114-115mph but its a 6spd and it won't 60' or 330' to save its life so the ETs always suck.

I would pattern my vette after my buddy's 383, steel headed 70 Nova that runs 11.50s@115 but his car is much lighter then my 71 AC car. I am sure my car stock is 3500lbs or so. His car is also more setup for the strip then mine will be...ie. skinnies, drag shocks, no sway bars etc.

CGGorman

Big blocks only have cooling problems when the cooling system is broken. Same as a small block with a broken cooling system.

You sure a iron bigblock is 300 pounds heavier than a iron small block, or were you comparing an iron BB to an aluminum SB?

Glensgages

He and I spoke afterwards, and neither of us think it woulda MPH'd much-faster:
he said the shift-light was lit well-before the stripe, and we figured-out it was turning about 5600 RPM, so the ZZ502 was about outta-wind at that point.....


That motor isn't so-much about the HP, but about the 567 ft/lb of TQ:
it out-ET'd the 468" by a tenth, yet got out-run by 4 MPH on-top, so it musta REALLY ran from 60' to 1000', then nosed-over some.....

Probably would've run best with 3.73 gears, a much-looser converter, and a bullet-proof rear-end.


11-eighties at a buck-fourteen

ajrothm

No not sure about the actual weight between a BB and a SB. I know an original 70' LT1 is listed at 3360lbs and the 70 LS6 was listed at 3478lbs but I believe the 70 LS6 in a vette had aluminum heads right? Maybe not but I thought they did. The 70' LS5 w/ AC was 3675. My std 270hp w/ AC and auto is rated at 3460lbs which is 215lbs lighter then the LS5 BB w/ AC.

Maybe the 502 is not the best way to go for MPH but in reality, HP is HP, not matter what rpm its at, it just needs to be geared correctly to make the most of it. I think if the 502 C3 in the story above had 3.36 or 3.55s it would have probably ran quicker(due to the converter being a little looser from less gear) and mph more being lower in the revs through the trap.

On my old pontiac 400 TA, I ran 3.42s with a 3k converter and ran 108-110mph depending on the air, when I went with 3.90s and a bigger solid lift cam, I never went over 106mph..not enough head flow and rpms available. That car was 3700lbs with me in it and that motor was lucky to make 400-425 CRANK HP.

Little Mouse

If you are going to spend a good deal of money for an engine,
the big block makes the most sense, very easy to make power
with, very good breathing heads. plenty of torque & hp to go with it.
with aluminum heads, water pump, and starter, they get fairly
light. They use to say a cast iron from intake to pan big block
680 pounds, same thing in a small block 520 pounds.

J. Swisher

If you look at the specs on the cam, you can see there is a lot left in in the 502
-Camshaft Duration @ 0.050" I/E : 224 / 234
-Camshaft, Lift (I/E) : 0.527" / 0.544"
This is pretty tame even for a lot of small blocks. Change to a better cam and intake will wake up the motor quite a bit, but of course at the expense of drivability

Bismarck

Personally, I don't like current GM big block crate motors. Their compression ratios are too low, they tend to use oval port heads and so on. The so called ZL1 is a disgrace compared to the original. The only thing good about a 502 is the displacement. I would much sooner build up a Merlin or Donovan aluminum big block and do it right (minimum 11:1 cr, juicy solid roller cam and AFR aluminum heads). It would be light and brutally powerful.

Little Mouse

World products awhile back had an aluminum rat block for a
little over $3500. very tempting.

Summerfun

Another thing about a nice BBC, when that Suzuki passes you at 50mph more than you are doing while going up a hill on the highway......

.....you gear back into third and let her rip into 4th and 5th, you catch up to the Suzuki within a few seconds and smile at him.

The looks on their faces are priceless

DRL502

Absolutely, ...
I replaced my 350 with the ZZ502, TKO600-5sp and 3.55 rearend.
Torque is there starting just above idle, at 2000 rpm, all the way till 5800 rpm redline. For the street, big displacement/500HP/500+ TQ, means the instance throttle response (at any speed between 0-100, any gear) has no equal for the $.

Plus the added bonus, the sound of a big block with Super40 Flowmasters...Priceless

ajrothm

Thats exactly what I like about them.. Relatively mild for making 500hp. Especially for $7500 carb to pan, even starter, water pump and flywheel. I want something thats going to get this thing in the 11s and still run the factory ac. My only drawback to switching to a big block from a small block is changing all of my accessories.

Atleast if I do a nice 383, I can still make it appear basically stock and original..within reason anyway. WHichever motor I go with, I am going to run a 3k converter and relatively tall gears, no more then 3.70s

I have been spending a lot of time getting everything on my car working like it did from the factory, kinda considering keeping the motor mild to keep the driveability 100% and the car not rattle and rock itself to death.. Kinda leaning towards the ZZ383. I know it doesn't make much power but it would cure my fitment issues and be mild enough for everything to work and not affect the integrity of the car. Maybe I should just shoot for low 12s... ZZ should get it there I would hope.