Not sure if this is the best forum section for this, anyone here ever buy one of the HO 350 kits GM/Chevy offered in the early nineties? This was the first time a US auto manufacturer offered a drive train upgrade kit of this type post sale of the vehicle that I know of. I ended up with one from a Dealer that bought a kit by mistake and couldn't return it.
Tony

 

Yep, very cool deal and was offered in the parts catalog for quite awhile too. Would like to have one of those ZZ3s

 

I wish they still offered the kit today. They made a lot of carbed LG4 and L69 powered thirdgens. If they are in good shape, the 1985-1987 Z28's have come down in price i've noticed compared to the IROC's. Would be great if they made this kit with the new ZZ6 crate motor that came out recently.

 

Yeah somewhere I have the catalog from '99 or so, the kit was still being advertised at that point.

 

I think there was some talk about that kit last year. I used to drool over that in the GM performance parts book back in the early 90's

 

I bought that brochure from my dealership when I swapped in my 350 HO. IIRC, the cost was $15.

JamesC

 

I'm fairly sure its in my 2001 GM catalog as well, will double check that. (edit: yup, its in my 2001 gm parts catalog)

 

I purchased the brochure about 2005 (but frankly, I don't think the kit was available at that time).

JamesC

 

Ive actually seen this kit supposedely dealer installed in an LG4 Trans AM car back in the day. I remember seeing the "350 HO" decals" and thinking I had never seen any other HO other than the 305. Boy it was strong. Ran in the upper 13s in the 1/4 of if I remember correctly.

 

A little more history of the HO 350 Kit:

The 350 HO engine was orignally released in 1989 with engine code ZZZ.
It had a 4-bolt main block, forged steek crank, 1970-1972 LT-1 "pink" rods, 9.8:1 compression pistons, a .480" lift roller cam, L98 production corvette cylinder heads, and a 1969-1972 Z28 high-rise aluminum intake.

To get "real world" data on the engine's performance, Chevrolet engineers installed a ZZZ engine in a 1989 IROC-Z 1LE. They used an open element air cleaner, a 750 cfm Holley carb, aftermarket headers, and a true dual exhaust (without cats). At this point, 1/4 mile time was 14.19 at "approaching 100 mph." This was written up in the February 1990 issue of Chevrolet High Performance magazine. The article specifically mentioned that the HO 350 was intended for "off-highway emissions exempt" applications and that "Chevy has no plans to produce Camaros with High Output 350-cubic-inch replacement engines"!

The October 1990 issue of Chevy High Performance reported that Chevy engineers changed to a "hybrid cold air induction system" consisting of an L69 air cleaner base and ducts, plus an open element air filter and lid. They made adjustments to the carb and distributor and switched to GM Performance Parts tri-Y headers and a GM free-flow stainless exhaust system. 1/4 mile time was now 13.1 seconds. This was still with the ZZZ engine.

The details of the 350 HO kit was written up in Chevy High Performance magazine in the February 1992 issue. This included a revised engine, coded ZZ3. The ZZ3 engine had a new lower profile intake manifold, a dual pattern roller cam, and "a revised valvetrain". (different springs and other changes). The kit was emission certified for 82-87 Camaros with automatic transmissions and either LG4 or L69 305 engines. It included a lot of additional parts such as the L69 air cleaner, dual-cat exhaust, ECM with PROM, transmission calibration parts, fuel pump and pressure regulator, and lower control arms. With the emissions certified configuration, peak HP was 308.4 @ 5000 rpm and peak torque was 365.8 at 3500 rpm.

Chevrolet installed the 350 HO kit in a 1987 Camaro Sport Coupe. 1/4 mile time was reported to be high 13 second ET at 98 mph.

It's really incredible to think that Chevrolet went to so much trouble to make this kit and get it emmissions certified. The fact that they had to make an all new intake manifold and a new cam showed they were serious.

 

They should have seriously put it in these cars from day #1 instead of a 145HP LG4! That would have fixed those Mustangs beating up on our lower engine optioned 3rd gens.

 

I wonder why they bothered with the 4-bolt block. It's not like it made 600hp or was used in an off-road truck or a boat.

 

My guess is that while the engine passes the emissions requirements, it probably couldn't pass the CAFE standards needed.

 

They could have also put in the headers and extra cats on our cars like the Mustangs and maybe it could have been a better fight. But then again, if they did that from the start, we probably wouldn't have had the 350.