gbarmore

Hey all, i'm looking to drop a GMPP turn-key 350 in my 80 and i'm debating between the ZZ4 and the Fast-Burn 385. They are identical motors with the exception of the heads. The question is should I pony up the additional $750 for the Fast-Burn version because the heads would create a better platform for future CAM upgrades given the better flow/larger valves, etc? I would eventually like to get this motor up to ~425+ reliable, streetable HP.

Here's how they stack up on the crate....

ZZ4 Heads: 355HP / 405tq
1.94"/1.50" valves
163cc intake port
58cc combustion chamber
10:1 compression

Fast-Burn Heads: 385HP / 385tq
2.000'' Int/1.550'' Exh Valves
210cc Intake Ports
62cc Combustion Chambers
9.6:1 compression

Funny thing is the Fast-Burn version is $750 more than the ZZ4 version but if you were to just buy the heads brand new, the ZZ4's and Fast-Burn's are the same price.

nonracer

I had the 385hp fast burn engine in an 84 monte SS it ran excellent in stock form , I guess it depends on how soon are you going to upgrade? If it going to be a few years go with the fast burn but if your going to upgrade soon get the zz4. I think the hot cam and rocker upgrades puts it around 400 or 410hp??

gbarmore

Nonracer, are you talking about the COMP Cams ZZ4 performance package? It includes a ***** Thumper CAM, springs, etc specifically put together for the ZZ4 Crate. They claim +64 HP which is pretty impressive.

Here's a link to the spec sheet if interested:
http://www.compcams.com/Company/CC/c...?csid=217&sb=0

It would actually cost less to buy the ZZ4 turn-key and the CAM kit than it would to buy just the Fast-Burn Motor. As you said this would put the motor at ~410 HP which is ~25 more than the Fast-Burn. Just not sure about that ***** Thumper CAM. I'm just learning about cams and how they work as a system with the other components in the motor, so any help would be greatly appreciated. Also wondering if that same CAM would make a good addition to the Fast-Burn motor to eek out even more ponies if I decided to go that route.

FWIW I have a TH350 with 3.08 gears, (Yeah I know, boring )

nonracer

I was just going off my memory ( getting worse with old age) Im not sure on the specs of the ZZ4 cam or the "hot" cam kit but either way you go you should put a higher stall speed converter and a little lower rear gear unless you do a 700r4 with a lower first gear.Gear and converter choice will make a big difference in performance.BTW my car had a 700r4 with 3000 stall converter and a 4.10 gear with a 315/35/17 tire.The converter was a bit too much around 2200-2500 would have been better.

nonracer

What about the zz4 short block and the zz430 top end? The price probably goes up but you get all the hp you want first time around.

jackson

Those ZZ4 heads make great upgrades to low compression dish piston L48 ... lotsa those still left ... you could probably easily sell ZZ4 heads.

the fastburns are great heads and have lots more power & potential ... but they aren't the cat's meow ... and may not not sell as easily as ZZ4 heads.

Dunno where you'll end up ... I'm guessing I'd probably start w/ ZZ4.

billla

Why not just buy the shortblock you want, and put on the heads/cam you want, vs. worrying about what the parts you don't want will sell for?

gbarmore

Hey Billa, I'm not really worried about selling the parts, but also didn't want to throw away $700 if I could avoid it. I was really hoping you might chime in here as I enjoy your posts and your practical approach. I know I have to start by telling you my budget first and foremost! That magic $ is 6K. I was leaning toward the turn-key motor because it's pretty much ready to roll, has a decent warranty, etc. My L48 has very few, if any donor parts that could contribute to a build. Not only that, but prior to buying my first vette 7 months ago I had never changed my own oil and now I am neck deep in a frame off and doing it 100% on my own. At times I question my own sanity, but overall it's extremely rewarding and I am committed to doing it right, not NRCS mind you, but 'properly'. Point is I have learned so much already but not sure I can soak up all that it takes to build my own motor just yet.

Anyway, I know enough because of people like you, and this site, thank you everyone!!) that my 2 bolt main really isn't a good base for a relatively high HP motor if I want it to last. I am not sold on a turn-key crate by any means, but if I were to go that route, picking the right base for future upgrades in important to me. I know I won't be able to leave anything alone for very long and want a good platform to expand on. My diff / trans also leave something to be desired, but $ flow issues will prevent me from tackling those projects until later. I suppose I could flip that whole theory on it's ear and drop in a 3.73 rear and a OD tranny and leave the motor alone... Decisions, decisions.......

billla

Thanks!

Setting aside your original engine is a good call regardless of the reasons. Nothing wrong with a 2-bolt, but waiting for a restoration sometime in the future is a great plan.

Turn-keys are nice - but the issue I always have with the GMPP engines is that they're not *quite* what I would buy for myself or for a particular application. But buying a completed shortblock and doing the final ***'y can get you pretty much right where you want to be. And it doesn't require the same level of engine building skills...just a little care and patience. Matching a solid GMPP shortblock with some great aftermarket heads and the right roller cam is a "some assembly required" but great solution!

63mako

Right base for future upgrades and you spending $6000. I would spend some of the future upgrade money now and get the package now not needing to tear it apart later. Don't care for the Powdered metal rods and you know you won't be happy long term with a 350. This is fully forged, new block, internally balanced, full roller, already have great heads, a great parts list and right setup long term.
http://www.ultrastreet.net/engines/4...treet_alum.asp

billla

Lots of good options The GMPP PM rods are fine to the power level the OP was seeking. But I agree that most of the GMPP GEN I SBC stuff is limited to right around 450 HP max. But the ZZ4, HT383 and other choices are good foundations - especially with the right heads/cam.

The 402 at looks like a great engine for the price with all the right bits...but $2K over budget right out of the gate...before it's in the chassis. I think the RPM would have to come off with the stock hood, and there probably needs to be a phone call about the pan for a C3...although I'm sure they build to order and would customize.

If the budget changes, so do the options - but there's a lot of power that can be had for a lot less than $6K

63mako

Budgets are made to be broken, it's a corvette.

billla

I just see a lot of projects that get stalled over money. It's made me admittedly hyper sensitive to having a real budget and staying within it as the key to success.

An engine you can afford in the chassis and running great is way better than the engine you can't afford that sits on the stand, uncompleted.

gbarmore

63 and Billa..... I get what both of you are saying and I can appreciate both views. 63, you are probably right when you say I will not be happy forever with a 350. Billa, you are right that the budget should be minded in order to actually bring the project to the street some day. While my budget is not set in stone, an additional 2-3K is a decent deviation, + I'm guessing that 500HP/TQ is going to wreak havoc with my stock tranny and diff which means lots more money to keep it safe and reliable correct?

uxojerry

If you upgrade to a crate 383 you will have a better platform for future mods. These projects are fun when you can afford them. A 383 will allow you at a later date to get 500hp, if/when you are ready to upgrade other components. You may decide that 400+hp is sufficient and not upgrade anything.

If you get into mods and look at the car as a whole, then much of the car will need upgrades. Drive train, suspension and brakes to name a few. If you upgrade those components then you will regret not going with a custom frame to start with, lol. It is an extensive list of expensive parts but a lot of fun if you enter with eyes wide open.

In all likelihood, you will find 400hp more than sufficient for your needs. Later you can upgrade to an EFI to eliminate the carb and get better fuel economy and performance without having to change the whole car.

You enter this project with the bank account you have, not the account you might want or wish to have, lol. Ive learned this the hard way.

gbarmore

So realistically what can one expect to be able to deliver HP wise to a bone stock TH350 and a 3.08 rear diff, yokes, u-Joints etc, before having issues on 255/60-15 everyday street tires (for now anyway)? I know there are many other factors including how heavy the right foot is, but let's assume i'd get into it a few times every time I take it out. I'm not looking to tear up my rear end and send fiberglass yard-sailing all over the neighborhood.... Bottom line is I want the power, but if I need to do other upgrades first I will to avoid damaging my freshly restored car. There must be some rule of thumb right?

63mako

A 3.08 will hold up better than a lower gear. Your trans is a pretty stout stock unit. An automatic is way easier on drivetrain components than a manual. Street tires will help a lot. The traction loss will be easier on everything but scary if your not used to it. No one can guarantee how long any stock components will hold up. 400 HP is pretty safe. 500 HP will break stuff if you hook up but so will 400. I used to tear out muncie 4 speeds regularly with a bone stock 350 because the car hooked hard. It does all depend on what you want the end result to be and how much your willing to spend. The L88 cars ran the same differential you got. They had 400 trans though.

TPIShark

I was not impressed with the build qaulity of the fastburn heads. I sent them back and got Edelbrock's. (E-Tec) Great quality, and were $100 cheaper at the time. Oh, and made here.

gbarmore

Thanks 63, Billa, Jackson, and everyone that contributed. I'll keep doing my homework and post back my ideas and questions as I move forward. Pretty sure if there is an "end to the internet" I will find it in the process of doing research for my restoration....! Now back to the garage to finish scraping undercoating off the wheel wells.....

billla

One last comment regarding your post about drivetrain limits - IMHO, it's not so much about that as it is about balance in the car...chassis, suspension and brakes. If your C3 is in great shape overall, then no worries. But if you still have work to do, then setting and staying in a reasonable engine budget ensures you don't end up with a car that goes straight, but won't turn or stop. The Corvette is a sports car and there's nothing worse than having a ton of power up front on old bushings, lousy brakes and skinny tires. Congratulations, you've made a Corvette into a Nova ;-)

Also, and this is probably going to generate some "heat" but...most folks have never felt an honest, well-tuned 1HP/CID at the flywheel. I can't count the number of folks that have come to me for a top claiming "500+ HP" where the baseline dyno showed more like a badly-tuned 350-375. Even an upgraded C3 is a handful with 350-375 HP...and way more so with 500...so bottom line is yeah - if you're going to make 500 HP, you should be planning on serious investments in the rest of the drivetrain, chassis, suspension and brakes.