The 402 finally called it quits so its tme for a new motor. I have a local builder (builds race motors for a living) that will put a killer 496 together for me (strong bottom end) but I have also been looking at the ZZ502 long block. I want a street motor that I can throw a little NOS at if necessary. I can't get real radical with the cam choice either way due to emissions here in AZ. I want it to run on pump gas as it will mostly be street driven (weekends only). By the time I get done I am seeing about the same dollar amount for each setup. So I guess what I am asking is if you were to make the choice.......... which way would you go, and why. Need help on the pros and cons.

I went away from the 502 in part because I didn't want the extra expense of having to buy a new oil pan. If that isn't an issue for you, it's tough to beat the GM warranty.

You're looking at roughly the same displacement, valve area, etc, etc. Not much horsepower difference to be had, to my way of thinking.

Well I'm pretty sure that, TECHNICALLY, you can bore the 454 out enough and stroke it enough for it to be 502 anyway...so depends on if you want price/custom components or a bit more pricey engine but with a good warranty.

I almost went with the ZZ502 as well. The only hang up for me was the fact I couldn't use a mechanical fuel pump. I didn't want to hassle with an electric, especially since my car would be daily driven. It's a good motor but that was a major factor for me. Good luck!

A 496 (made from a 454 block) uses a 4.25" stroke which is a quarter inch longer stroke than the 502's 4" Stroke. The longer stroke motor will be harder to hook up on the street, but I would recommend whichever costs less.

Originally posted by Bob Tiley:
A 496 (made from a 454 block) uses a 4.25" stroke which is a quarter inch longer stroke than the 502's 4" Stroke. The longer stroke motor will be harder to hook up on the street, but I would recommend whichever costs less. why would a stroker be harder to hook up on the street?

leverage.

Well, when you do take the car out for a spin, what is it's primary use? Do you cruise? Take it to the track? Or you looking for a thumpin street car? If it's gonna spend it's time at the track when you take it out, then you'd be better off getting the 496 or maybe even a 540. If you're looking for a cruiser then I'd say go with the 502. If you're looking for a streetable car to kick some tail but pump gas friendly, then why not go with a decent to mildly built 496 and a 150 shot of nitrous? Either way, it's your call...good luck and have fun! graemlins/thumbsup.gif

have you guys from az. asked your dmv if you have the classic plates,that it has to be smogged????
after the initial inspection for the classic plates.before i built my current motor i inquired with dmv here and had it inspected before the motor swap,now i dont have to smog it...
shane

Ramjet 502! Gives you power, some minute measure of economy, and has the full warranty. Runs on pump gas, is substantially quieter than the mild 454 it replaced, and makes a boat load more torque and HP.

Before you weigh the pro's and con's..
What do want this car to run at the track?
What rpm's do want to cruise at?
Then decide..

I went with a 489 .30 over not .60 and I'm very happy. Better rods and crank in my 489. I all ready had oval ports and wanted to use my heads and I also had the 454 block so it was a no brainer for me. The 540 would be killer and sometimes not more $$$. No replacement for displacement.

If you re-use your 402 heads and buld up a 496 you might have less $$$ invested and have a great runner as well.

GM built the ZZ502 very mildly. It has 9.2:1 compression and a very small cam for 500 cubes. Plus the oil pan does not fit a chevelle. On the other hand it should last forever and with the torque it makes, it should run pretty good with very little gear and converter. If the 496 is being built from scratch IMO it wouldn't be hard to make more than 502hp with one. If you have a 454 block already it is a good choice too.

You can build a 496 that will make more power,
but to feed a 496 making more power you will
probably need an electric fuel pump anyway.

And the 502 is so mild, for a car thats going to see a lot of street duty,
its a very easy to live with engine.
Its a simple plug and play kinda of deal,
you don't have to check the math, or find a machinist, our search for parts.

If your a good tuner, engine builder, with enough experience, and know how, sure, you can make the 496 a winner.
But if your a novice like me.
Its still pretty hard to beat a ZZ-502.

I haven't seen it listed yet,
but isn't there supposed to be a ZZ-454 on the way,
that uses the 454 H.O. short block, with the ZZ-502 top end ?

That would be a nice package.

He, He!! I would really like to build a 4.530" b x 4.375" s = 564" motor using a stock .060" overbored 502 car block, a Mark IV crank adapter kit and 4.375" crank, custom 6.44" long rods and needed pistons!

But again, I dream alot!!

It should be a dandy street motor with no more then a set of stock worked over rect. heads, about 10 to 1 CR., and a 245 to 250 duration at .050" solid cam....

AND it shouldn't cost all that much to make, imho..... Just a step above a 496 like a 540 is..

pdq67

Originally posted by 68chevelle533:
GM built the ZZ502 very mildly. It has 9.2:1 compression Actually, they have 9.6:1 C.R.

Originally posted by Bob Tiley:
...The longer stroke motor will be harder to hook up on the street, but I would recommend whichever costs less. tell me about it. my 462 has a 4.21" stroke. :D

here's a somewhat foolish reason to go with the 496. the 502 has become something like the 350. everyone and their uncle has one. Okay, maybe not quite as popular, but every magazine car has a 502 engine in it. Be different, run a 496.

Never had the pleasure of riding in a 502 car. But, I did take a ride with Jim Haas in Pigeon Forge a couple weekends ago. He has a beautiful '71 SS Conv. with a very, very mean 496 runnin through a TH400 and 3.73 gears.
Beleive me, it is all the engine I would ever need. It was scary fast! Very scary fast.

Dwayne

Thanks for all of the replys. I may be taking a slightly different twist. I talked with another builder and he will put together a 540 with a Dart block, Eagle 4340 internals, and JE forged pistons in a short block. I have a nice set of open chamber oval port heads that have been "mildly" cleaned up on the car now that were just re-done. I can use my RPM air-gap, same carb, my MSD dist, etc. I figure I can build a somewhat docile street motor that can handle a 200 shot of nos and end up with good manners and performance. Any bad feedback on the 540 set up that I should be looking for? Once again thanks for the help!

Thanks for all of the replys. I may be taking a slightly different twist. I talked with another builder and he will put together a 540 with a Dart block, Eagle 4340 internals, and JE forged pistons in a short block. I have a nice set of open chamber oval port heads that have been "mildly" cleaned up on the car now that were just re-done. I can use my RPM air-gap, same carb, my MSD dist, etc. I figure I can build a somewhat docile street motor that can handle a 200 shot of nos and end up with good manners and performance. Any bad feedback on the 540 set up that I should be looking for? Once again thanks for the help!

The oval ports will not support a 540. It would be a complete waste of money to put together that short block and top it with factory heads. You will need at least 400 cfm ports to do justice to that beast.

This is definitley the first time I have ever seen "540" "200 shot of nos (hehe, you said nos)"Docile" and "Street Motor" used in the same paragraph.

Good luck and buy stock in oil. with them hefty 3 mpg's your gonna pull in you could make yourself rich by making yourself broke. :D