Slow Iroc

Hey guys. My buddy has an LO3 ex cop car (91 Caprice), and we want to start doing some basic mods untill he has enough to the fat ole' 400 sb.

I plan on making a sutom dual exhuast for him, but last I remember, LO3's had real ****ty heads and exhuast manifolds. What is the collector size on a stock LO3 manifold?

I already have an open air cleaner for him, but what else do you guys suggest? The car can't be down for more than abuot 8 hours at a time, preferably less. Grinding the TB doesn't sound appealing, so let's hear what you have had success with. Edelbrock intake? TB Spacer? Give it too me guys, I need the help.

Tas

well if its a cop car it should have the LO5, the low output 350. You could start with good exaust like 1-3/4 headers that the 400 would probably need.

------------------
-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

Slow Iroc

The LO5 was only made *avaliable* in PI Caprices (not the civilian counterparts), however, the LO3 was the base motor for the PI cars.

kdrolt

I agree that the 91 9C1 had either the 305 or the 350 as engine choices. The open element will be less restrictive and it will make a lot more noise, but you will be throwing away the benefit of cold air --- and you need as much as you can get with only a 305.

He/(you) might start here:

http://www.impalassforum.com/cgi-bin/ultimatebb.cgi

Engine mods on LO3/LO5 have been discussed there, and much of it borrows from the TBI mods on ThirdGen. The main differences are that the 9C1 Caprice is 500-800 lbs heavier than an Fcar, so one shouldn't overdo the cam swap.

For mods on the '91 model, see the Caprice Forum; the rest of the web site has mod and info concerning the rest of the car, and the 1977-1990 and 1991-1996 models essentially share the same frame; so many of the mods made popular by the 94-96 WX3 cars (Impala SS) work on ALL the '77-'96 models.

Briefly, you can either make him the custom dual exh (you will probably need the 94-96 crossmember with the dual humps for the pipe pass thru), or go with the 92-93 9C1 LO5 Y-pipe, an aftermkt low-restriction cat(s) and a good aftermkt muffler.

Do the TBI mods; read the vFPR discussions on ThirdGen under the TBI forum (a cheap band aid approach to getting more fuel on demand); truck tall lid on the pre-1991 air cleaner and the cleaner body be modded for an extra air intake snout (dual snorkle); bump the timing SLIGHTLY; and lastly cam swap of no more than the 94-96 LT1 or 96-99 L31 factory hyd roller camshaft (same cam). Yes, it's a mild cam but it's much better than the LO3 cam, and you can get them used for next to nothing, and it will help a lot without overcamming the LO3 in a 4200 lb car.

If he's going to eventually do a 400 sb, then I don't see that he should waste money on an aftermkt intake... unless he can get a used one. A heat shield (stainless steel cookie sheet suitably cut to fit) under the TBI would be useful/cheap, as would a NON-aluminum spacer under the TBI. If you space the TB up, it will reduce the height you have to use the truck air cleaner lid, so that's a tradeoff.

The other resources are:

http://www.9c1.com

and the 9C1 digest via http://yahoogroups.com

For sensible street use, with the cheap mods and a mild cam swap, per above, the 305 should be able to make 220-230 fwhp and 270-280 fw ftlbs torque. That will put the car at around 16.0 in the quarter at 82-83 mph. Not great, but then again, not bad considering the low cost and the mild mods... and it will be a full second faster than the stock engine. HTH. - Ken '94 9C1


[This message has been edited by kdrolt (edited August 07, 2001).]