MDC9966

I was looking through my JEG's catalog yesterday and comparing prices on crate motors. My 86 with Aluminum headed L98 will at some point need a rebuild or replacement. I had considered going with the ZZ4 and swapping my TPI setup, then I saw the 350 HO offered at about $1300 less. It does have cast iron heads but they are the new style centerbolt so I think my currrent TPI intake will fit. The compression is listed at 9.1:1 vs the L98 at 9.5:1 vs the ZZ4 at 10.1:1. It is advertised to make 330HP @ 5000 rpm and 380 ft.lbs. torque @ 3800 rpm with a max rpm of 5500. The ZZ4 is 355HP, 405 ft.lbs, torque @ 3500 rpm. The ZZ4 is more but both are stronger than the stock reported numbers.
Both engines have 1.5 rockers, and 4 bolt mains. The ZZ4 does use a forged steel crank and larger cc heads with as listed a roller cam.
I know the ZZ4 must be a stronger engine, but is the HO a good replacement for a stock L98, even though it has cast iron heads? The stock L98 in my 86 is only listed at 235HP so I'm thinking it would be. If anyone has experience with these please chime in.

65Tuxedo

I went from a 300 hp to a ZZ4 in my 65. The 300 was fun to drive, but the ZZ4 is a completely different and much more aggressive car. It was a straightforward swap. Water pump, flywheel, heater hose elbow were about the only changes. My exhaust manifolds did not match the cylinder head ports, but a template, grease pencil and grinder took care of that. I love this engine. It is remarkably strong and never misses a beat. It is common for people driving my car for the first time to take off in third gear and not even know it. I have 2 1/2" manifolds and sidepipes, the sound is great(except after about an hour!)

GregP

Check out the ZZ430 and ZZ450 at Sallee Chevrolet. Looks like the most bang for the buck out there to me.
http://www.sallee-chevrolet.com/Crat...rformance.html

-Greg

-=Jeff=-

I would go the ZZ4 route over the HO 350.. Better parts and performance..

If the ZZ430 and ZZ450 are using the Fasn burn heads.. you will need a different intake since the fast burn heads have the raised runner set-up.

Scoggin Dickey sells a TPI base that works with the Fast Burn heads

Marks69BB

Curtis - Keep in mind, you are comparing the crates which are typically rated at GROSS HP versus the L98 which is rated at NET HP. Your L98 is running ~300 GROSS HP so you wouldn't see much improvement with the 350HO or even the ZZ4 IMO. Look at the higher HP ZZ430 and up as Greg mentions or I think you'll be dissappointed. Also, not sure if you could drop an LT4 in there (not a C4 guy) but a buddy of mine is getting ~400hp+ Rearwheel HP (~550 Gross HP!) on an LT4 in a 90-94? with a sweet cam and some head work. You may be able to get a used LT4 at the junkyard and build it cheaper than a crate.

yoslambo1@cs.com

i was gonna get a zz-4 crate but someone on the forum hooked me up with http://www.allchevyengines.com i got a 430+ hp 383 engine with dart pro 1 aluminum heads, full roller cam setup & forged pistons for $4000.00 including shipping!!! it came with a 90 day guarentee (good for a performance engine). its being built now. i should have it next week. i plan on installing the following week. i will post how everything works out once its installed. in my opionion a zz-4 isnt the best bang for your buck. especially if power is what you are after. good luck whatever you choose. :cheers: