Chevy & GMC Vans

what is the difference between a typical 4.3 and a 4.3 HO? The van I just bought is a 1989 Astro RS and My friend at the dealership told me that all RS and GT models came with the HO motor. But he didn't know what the difference was internally. Anyone?

markmitchinnh wrote:what is the difference between a typical 4.3 and a 4.3 HO? The van I just bought is a 1989 Astro RS and My friend at the dealership told me that all RS and GT models came with the HO motor. But he didn't know what the difference was internally. Anyone?

I have a GT, and the RPO sticker codes dont show anything different, re: the engine, than any of my other Gen 1 Vin Z vans.

The only HO engine I know of is the VIN W engine offerred from 93-95, with the Balance shaft, leightweight rotating assy, CPI spider intake manifold, and the way hotter cam. This engine was never offered in any GT or RS van with a Z in the VIN (that is probably all GT & RS vans).

Just a side note: Any Sales person at any dealership - is not a reliable place to gather accurate tech info.
They just wanna sell it to ya and will say about anything to do that.

The man that told me about the HO engine is a parts man of 30 years for GM. He called me today and told me the HO engine was actually different in the cam and the exhaust Y pipe was bigger. But he also told me the parts are no longer available. This Engine was basically a trial thing and was not offered in all the RS or GT models. So mine may not be the HO motor. I looked under my van and the Y pipe looks the same as any other I have seen.

I've seen a list of all the cams that GM put in GM 4.3 auto engines.
Maybe the RS/GT had the "* '90-'91, VIN Z, Astro/Safari" cam listed below?
My GT exhaust looks as wimpy as the other VIN Zs I have had.
Dont think I can find which camshaft it has, from RPO codes though, but it runs just the same.
Maybe someday I will be taking that engine apart enough to find out, but not too soon I hope!
list of stock GM 4.3 cams, Copy'd from---> http://www.syty.net/forums/showthread.php?t=15850
* '96-'00, VIN W, w/ balance shaft
- Lift (I/E) - .415/.429
- Dur @ .050 (I/E) - .191/.195

* '93-'96, VIN Z, w/ balance shaft
- Lift (I/E) - .376/.402
- Dur @ .050 (I/E) - .183/.193

* '92-'95, Vin W, w/ balance shaft
- Lift (I/E) - .432/.440
- Dur @ .050 (I/E) - .208/.208

* '91-'93, ZR9/Z79, Syclone/Typhoon
- Lift (I/E) - .351/.386
- Dur @ .050 (I/E) - .179/.195 (Ductile)

* '90-'91, VIN Z, Astro/Safari
- Lift (I/E) - .403/.450
- Dur @ .050 (I/E) - .202/.213 (Steel)

* '87-'94, Vin Z, w/o balance shaft
- Lift (I/E) - .351/.386
- Dur @ .050 (I/E) - .179/.195 (Ductile)

Actually, I just figured out the way to tell if you have the GT/RS HO 4.3 is if it has a 'B' in the VIN instead of a Z.

doyoulikeithere wrote:Actually, I just figured out the way to tell if you have the GT/RS HO 4.3 is if it has a 'B' in the VIN instead of a Z.

OK-but you lost me here.What does a HO 4.3 do for you??.I guess I am asking what is better about it??.

HO usually stands for High Output....and usually has a little extra horsepower