Now that i have found out what engine is in my car , thx to the guys on this forum, i am in unsure what aftermarket exhaust to go for. I have read that the first modification to make is the exhaust as the std exhaust does not allow the engine to breathe very well. I live in england and emission laws are not that strong, my mate is a M.O.T inspector so i can get past them, so i have approached a local exhaust company to make me a straight through system. two questions though 1. can anyone see any problems with this idea 2. are the std headers( is that the same as manifolds) good enough to keep or can anyone recommend good aftermarket ones
. One final question is in regard to the std transmission is it good enough to cope with modificatoins to the engine like heads, cams, exhaust etc ( also what is the std transmission code for a 1983 Z28 auto box). Sorry for all the questions but i am new and this forum is superb

 

Headers are a tubular replacement for the cast-iron exhaust manifolds. They not only allow greater flow with less restriction; they also use the inertia of the escaping gases, to complete cylinder evacuation at the end of the exhaust stroke. Well-designed and well-chosen ones will actually create vacuum at the exhaust ports.

I'd suggest getting one of the better-quality ones, that are specific to these chassis; such as SLP, or Edelbrock TES. Ceramic coating makes a BIG DIFFERENCE, not so much in the power output, but in their longevity, and in the amount of underhood heat they create (which translates to longevity for everything else under the hood). In either case, DO NOT get the ones that the book will list for a 83 carbed car, except possibly for the L69 (HO). The problem is that the exhaust you now have, for LG4, has a REALLY TINY cat, and Y-pipe, and intermediate pipe. So anything that "fits" a 83 Z28, will PRESERVE THE BOTTLENECK, except for the L69 stuff which is a bit more $$$$ and uses an unusual flange instead of a slip-fit. In a perfect world, I'd suggest SLP 1¾" ones, for a 88 350 TPI with a single cat; that will give you a 3" slip-fit at the output. You'll find that the parts you can buy over the counter are probably going to give better results than any custom exhaust, and the cat for that application isn't very expensive at all. If you go that route, you can then buy an aftermarket exhaust "kit" such as from Hooker, Flowmaster, Dynomax, etc; and it all just bolts right up exactly like the factory stuff.

For a cam, I'd suggest a Comp Cams XE262.

Your transmission is a 700-R4, 4-speed automatic w/overdrive. It's reasonably strong, for what you've got in front of it, it'll be fine. Like anything else, it can be iomproved on though. The biggest things you can do are to make sure the throttle valve cable is adjusted properly (that affects both how it runs and its durability), and maybe put a looser torque converter in it.

Another thing that car (CAR, not engine) needs, is rear end gears. It probably has 3.23 gears, at best. 3.73s will wake it up.

 

once again RB great info. Is the cam change on a V8 a fairly easy job to perform, i am a fairly good D.I.Y mechanic but have never worked on american cars before although i am itching to get my hands greasy. Unfortunately i have already booked my car in for a custom exhaust, would you rcommend buying the headers first so that the garage can match up the custom exhaust to them.

 

yes.

 

You might want to look up "Willie" on the History boards, he has the best dual exhaust setup I've seen for ground clearance and possibly performance too.

Of course, if it were me, I'd just cancel the appointment for the custom exhaust and save your pennies (or whatever your smallest form of currency in england is ) and order a pre-made cat-back.

Everything from the stock manifolds, to the tailpipes need replaced, everything in there is a restriction.

 

could anyone post a link to a web site that i can order a good exhaust from please. Stupid question i know but what is a cat-back

 

Cat-back = everything behind the cat

Here's a typical one from Hooker at Summit. There are others available from Dynomax, Flowmaster, SLP, Borla, Edelbrock, and maybe more I'm just not thinking of off the top of my head. You can get any of those from Summit.

Here's a cat that bolts right up

Note that if you use parts like these, they fit to the factory exhaust hanger locations, and follw the factory routing. They bolt directly up to the various headers that are designed to bolt to factory exhaust. In other words, no fabrication, no risk of anything not fitting, you can put them on yourself if you want to.