ZZ383?

[farmer]

After some thought and consideration I am leaning toward buying the ZZ383 engine from GM Performance at a local dealer. I have considered othe engine builders, but because I live in Canada, import duties become prohibitive to bring in an engine purchased in the US. I can buy the block with aluminum heads for $5100.00 Please endure my ignorance as I ask several questions. Will the stock intake from my L48 perform adequately? What about the stock carb? Should I go to HEI, or stay with the stock points ignition? Will stock exhaust manifolds perform adequately? I have shied away from headers for a couple reasons....longevity and heat dispersion under the hood. I have the turbo 400 transmission with 3.08 rear diff. Do I need to increase stall speed? Would performance be acceptable without tranny changes? Thanks for any input. Ben

 

[Crimson Thunder]

If you want to keep using your stock manifolds and other parts on the new motor,you might want to check out the 383 that comes with the Vortec heads.It doesn't put out as much horsepower but it is a torque monster that would work great with your 3.08 gears and wouldn't require a converter change.It will require a Vortec intake that may have a hood clearance issue.

 

[Koop]

I'm pretty sure I could have used my stock intake manifold, but why spend all that money on a ZZ383 and not put a good High Performance Aluminum Dual Plane intake? Regarding the exhaust, again I'm pretty sure the stock exhaust manifolds will work (I think they may have been on my car for about 5 minutes with the ZZ383), but you'll likely want larger exhaust with headers, I don't understand the heat issue you mentioned nor the longevity issue, Thorley headers are your friend! They do drag over speed bumps on occasion but you GOTTA HAVE HEADERS and some Magnaflows! You can't make power if you can't get the air in and out. I think I put a 2000 stall converter in and there is an electronic ignition conversion that went right inside the stock distributor that works great. The Quadra Jet works excellent as it moves plenty of fuel, more than the 383 can suck in. You will need to have it rejetted though.

The HT383 is a truck motor, you have a Corvette, not a truck. You're on track with the ZZ383.

If cost is a factor have a look at the ZZ4, it's a great set up and quite a bit less expensive when it's all said and done as it comes with more of the good stuff attached to it from the factory.

I wanted to change my 3.08's to 3.73's and put in a 700R4 but my mechanic and my transmission shop convinced me that it was a bad idea and to at least try the car with the Turbo 400 and 3.08. I'm happy I did, it works awesome with the (not quite) stock trans and rear.

BTW, since you have a 1974 I don't know if you can use a single plane manifold but if you can there is a 15HP (or so ) benefit. Dual plane sits lower and was required in my '69 so I could keep my stock sleepy looking hood. :z

 

[fine69]

...I have shied away from headers for a couple reasons....longevity and heat dispersion under the hood...

Ben,

Excessive header heat is certainly a valid concern. Check out Jet Hot header coatings (http://www.jet-hot.com).

They offer headers that are coated both on the outside AND inside, or you can send them used headers and have them thoroughly coated. They have a free promo video that you can order online.

Ralph

 

[Koop]

I've had headers in my car for many years, I feel free to run it to the local desert 110+ degrees. How is this harming my car?


I understood the heat wraps ect., were to enhance the exhaust flow and help the air get out smooth and fast.

 

[farmer]

Thanks for the tips guys. Koop, interesting to hear of your experiences as it seems you have a similar setup to where I am heading. I don't want to alter my hood, but do want performance(obviously), and will be looking for the intake manifold that delivers both. Happy to hear you have those tall gears and are happy with performance. When I bought my car the first thing I did was blow my rear diff, so I replaced it with the same 3.08. So it is 5000 miles old and I am not wanting to change it too soon. The header heat thing comes from my past experiences with headers and all kinds of heat under the hood. My corvette cabin is already a oven and I was afraid this would make it worse. I did install ball valves in the heater core hoses and that helped immensely. I guess I was thinking driver comfort....not problems with the car, although there may be some if it is too hot. Ben

 

[fine69]

I've had headers in my car for many years, I feel free to run it to the local desert 110+ degrees. How is this harming my car?


I understood the heat wraps ect., were to enhance the exhaust flow and help the air get out smooth and fast.

I was referring to heat with respect to comfort level, not how it may harm to the car. With summer temperatures of 100+ degrees and 98% humidity here in Maryland, driving an old Vette can be brutal.

 

[Koop]

I was referring to heat with respect to comfort level, not how it may harm to the car. With summer temperatures of 100+ degrees and 98% humidity here in Maryland, driving an old Vette can be brutal.

Oh, comfort level!

I can't say I ever noticed a difference between headers and stock on that issue. If my car is hotter inside due to headers I sure can't tell (it's roasting hot in there). I don't see where headers would be any hotter than the cast iron 300lb manifolds that came with the car. Even if they are slightly hotter, IMO it's worth it.

I wonder how much weight came out of the car with the aluminun intake and exhaust, aluminun heads and aluminum pistons? Making the old sled a bit lighter is a good thing.

 

[Koop]

Farmer,

Intake is GM12486570 (I got that off the manifold), it's an aluminum dual plane so it would fit cleanly under the L48 hood. The original cast iron manifolds rob horsepower.

Headers are Thorley, I didn't use the wrapped or coated for a few reasons, the HP gain is apparently minimal on this motor, IMO they don't look good and most of all I like Chrome.

It is a GM ZZ383.

I haven't been able to stop by The Corvette Shop to get you the stall or the size of the jets, but I will shortly.

 

[Evolution1980]

After some thought and consideration I am leaning toward buying the ZZ383 engine from GM Performance at a local dealer. I have considered othe engine builders, but because I live in Canada, import duties become prohibitive to bring in an engine purchased in the US. I can buy the block with aluminum heads for $5100.00 Please endure my ignorance as I ask several questions. Will the stock intake from my L48 perform adequately? What about the stock carb? Should I go to HEI, or stay with the stock points ignition? Will stock exhaust manifolds perform adequately? I have shied away from headers for a couple reasons....longevity and heat dispersion under the hood. I have the turbo 400 transmission with 3.08 rear diff. Do I need to increase stall speed? Would performance be acceptable without tranny changes? Thanks for any input. Ben

I thought the ZZ383 already had an intake manifold on it???
Stock carb is a 750cfm and will work just fine. However, you will benefit greatly by getting it retuned/rejetted.
Stock exhaust manifolds should work, however you're likely going to lose a lot of power with the stock manifolds. Getting rid of the stock manifolds on just a stock engine makes a huge difference. Keeping the OEM manifolds on a newer higher performance engine certainly ain't going to benefit it any! :crazy
As for headers and heat disappation...well, your OEM manifolds are cast iron which will retain heat longer under the hood. Aluminum (and coated headers as mentioned above) will disappate the heat more quickly and cool much more quickly.
TH-400 is strong enough to handle the engine. It just sucks only having 3 speeds... :eyerole
Proper stall speed selection is determined by your engines output and/or in what RPM band you intend to do most of your driving.

BTW...Only after I bought my Hooker ceramic coated headers I found that I could have gotten the same headers from JetHot with a better coating for LESS money than what I paid at Summit Racing.

 

[Koop]

The ZZ383 doesn't come with all the goodies that the ZZ4 has, so no intake... ZZ4 vs. ZZ383 makes the ZZ4 a much better value (I paid extra for snake oil)

About the coated headers, I have yet to read an independent report of RWHP for stock exhaust manifolds, then RWHP for a set of headers, then RWHP for the same set of headers after jet coating. All by the same guy, same dyno, same weather, same day.

Until then, jet coating is just snake oil in my book ;squint:.

Would someone please show me some results? All I've seen is a bunch of mumbo jumbo theory, I want dyno facts.

 

[Evolution1980]

About the coated headers, I have yet to read an independent report of RWHP for stock exhaust manifolds, then RWHP for a set of headers, then RWHP for the same set of headers after jet coating. All by the same guy, same dyno, same weather, same day.

Until then, jet coating is just snake oil in my book ;squint:.

Would someone please show me some results? All I've seen is a bunch of mumbo jumbo theory, I want dyno facts.

Highly unlikely that you'll find anyone but a magazine that can do the comparo you talk of. However, I will say that I like the coating for two purposes:
1) It's visually much more pleasing...unless your 67Heaven who likes everything under the hood to be flat black.
2) Longevity of the headers. No rusting, no paint fading/cracking, etc. Which then leads me back to reason Number 1. :cool

 

[Koop]

Highly unlikely that you'll find anyone but a magazine that can do the comparo you talk of. However, I will say that I like the coating for two purposes:
1) It's visually much more pleasing...unless your 67Heaven who likes everything under the hood to be flat black.
2) Longevity of the headers. No rusting, no paint fading/cracking, etc. Which then leads me back to reason Number 1. :cool

I'm in So Cal, we don't have no stinking rust!

 

[Tom Bryant]

If I may interject here, my opinion of buying headers already coated is that it's a mistake unless you have had prior experience with that exact application and know that they will go in unaltered. As soon as you dimple a tube for clearance you have cracked the coating and rust has a place to start. Now you have to either live with it or get the header recoated. Why pay for the coating twice. Get the header raw and then install it. If you have to do any modifications make sure everything fits.Then take them to a coater. Money saved in the end.

Tom

 

[Glensgages]

If I may interject here, my opinion of buying headers already coated is that it's a mistake unless you have had prior experience with that exact application and know that they will go in unaltered. As soon as you dimple a tube for clearance you have cracked the coating and rust has a place to start. Now you have to either live with it or get the header recoated. Why pay for the coating twice. Get the header raw and then install it. If you have to do any modifications make sure everything fits.Then take them to a coater. Money saved in the end.

Tom

[Richard Dawson]

"..... survey-says.....

NUMBER ONE ANSWER on the board, Darlin' !!!!!"

[/Richard Dawson]

Jet-Hotting a set of exhaust headers is the best economical-move you'll make if you plan-on keeping the car any significant length of time:
I had headers (and wing-struts, front A-arms, rear-end housing, and several miscellaneous pieces ) for a rear-engine dragster Jet-Hot'd in '94, and although the car is now on it's 4th owner, those pieces look as-good-as new.


While a ZZ383 doesn't come with an intake manifold, carb, and ignition, and the ZZ4 costs less, figure-out what it might cost to get those pieces for the ZZ383, and compare that price against the ZZ4:
now.....

..... figure-out how-much money it'd take to get that ZZ4 (355 HP / 405 TQ ) to match the ZZ383's stated figures of 425 HP & 449 TQ, and it won't take-long to realize those additional 70 HP & 40 ft/lb of TQ ain't gonna come cheap.

The ZZ4 makes good small-block power, while the ZZ383 makes derned-near big-block power, and doesn't weigh any-more:
it also would provide a foundation for a large-displacement / higher out-put small-block in the future, with it's stroker-crank, clearenced block, and it's GMPP FastBurn heads

 

[Koop]

^^ And a third reason.

So the first time you bang your headers on a speed bump, there's a dimple.

Chrome and Nickel baby, chrome and nickel.

 

[Evolution1980]

Good call on "check clearances THEN coat 'em".

Koop, regarding your comment about no rust in So-Cal.... :L

 

[Chuck-75]

Iv'e installed a ZZ-383 using a 200-R4 trans. the fit is perfect. Hooker side pipe headers, the #1 pipe touches the steering pitman arm. (need to dent the pipe or try a rack and pinyan setup), using a edelbrock dual plane air gap intake so a new hood will be in order, a demon 750 vacumn carb.(with these vortec heads you can use eighter,vortec intake or old style), .. My 75 is already a pointless distributer,but if you have a point distributer car?, ive read a post recently that you have to go to a bigger wire for the distributer to work..(other wise after startup the car wont stay running?)
sorry been lazy to get the car to the first start, but soon.
(been caught up if the -while im at it symdrome- dash and intieor stuff-, hope this helps?.

 

[Koop]

The Thorleys (now known as Dougs Headers) are a perfect fit and are known not to have leaks around the gaskets and they stay that way unlike some other brands. With some items the extra cost is worth it in the long run.

(Evo, is Ohio in the "rust belt"?)

 

[farmer]

Thanks for all the tips gentlemen. I am scrounging to come up with the $$$ for the ZZ383. I don't wish to do this twice. Unfortunately mama found out how much the ZZ383 costs and has put the brakes on my plans....for now. I have to spend some more on other things first. Keep it fair. Ben