Depending on the motor, a TKO 500/600 may well be a downgrade, as those have wider ratios than the Muncies.



1-2 and 2-3 on the TKOs and T56s are wider, so theoretically could lose speed depending on the torque curve of the motor.

You do get a better launch gear and a better highway gear. For maximum "performance", a transmission like the ROD is probably best.

 

Gee,
I'm inclined to say:
Pull your original engine, store it safely AND install a GM crate motor.
It seems to me you are truly in search of more power.
New heads, valve train work etc can be pricey. $2,000+
A replacement Z4 crate engine is: $2099 +$165 S/H to your door OR for the bold, $3,999 for More HP/Torque (Summitt Racing)
Then, you protect your original engine.
Just an opinion, an alternative to new heads etc., again which can be pricey.

 

Not sure what a Z4 is.

A ZZ4 is $4000, give or take, and isn't all that exciting of a motor these days. Yes, it's rated at 355 hp, but on the gross scale. It's basically an L98 with a dual plane intake manifold and a slightly more aggressive than stock cam.

Vortec heads blow the L98 heads out of the water, let alone AFR, Trick Flow, etc.

I don't think the ZZ4 is a good value for the money, but it's certainly a safe bet.

 

Im on board with heads and emissions tune being the choking factor of your L-82. The cam is a great cam for it's era but upgrading to the Xe268 would definitely wake it up a little more. If your bottom end is sound, a set of conditioned vortec heads, Edelbrock RPM, a carb upgrade and a re-curve would give you quick a nice bump for not too much $$$. Of course you also need free flowing exhaust. If you want new economical USA made heads I suggest you check out RHS. But you really could get everything you're looking for out of a set of refurbished vortecs imo! Good luck!

 

Thats Okay...
A Z4 is a GM Performance 350 Turn Key crate Engine. (Yup, GM part #)
Price, w/out sale is $4,399 +$175 S/H right to your door.
So, lets go the "machine the heads OR replace the Heads" route:
Edelbrock "GM" 350 W/ A 70 cc chamber for invreased compression(that Is what he first asked about) $1,400 + S/H
Now, it's a L-82 Throw in a set of gaskets:$35
Add a Stage 1 rebuild and restoration service to the Quadrajet; $199
That brings the price for the little "upgrade" project to $2,000
What kind of performance does this lil 350 L-82 have now?
By throwing in a GM Part number:19201330 - ZZ4 350 (TURN-KEY)
• HP: 355 @ 5250 rpm
• TQ: 405 @ 3500 rpm
You get huge performance and no fear of damaging your investment car. Your original is stored safely in the garage.

 

....and this is why I am thoroughly satisfied with the way my 78 L-82drives and performs. I'm not looking to make it faster...
But if I were to MOD it, number 1 on my priority list would be to protect my original engine.
Sure, it's not an expensive (the 350) engine like the Hemi in my 70 Superbee...but hey, even that gets beat by the new cars today.

 

I am in a simliar position with my 78 L-82 4 speed with 66,000 miles (see previous post).

I currently have a weak #6 cylinder (90 PSI) versus 160-165 PSI on all other with a compression check. After a leak down test, I am going to pull the 882 heads, assuming that I have a head problem and not a piston issue, which I believe is the case. I want to keep it as original as possible and have it still be the original engine, not a crate motor. It says L-82 on the hood and no disrespect, but not ZZ4. Just my opinion.

The plan is to keep the stock bottom end and replace the 882 heads with AFR 180 65 CC heads with a Howard's Roller cam. Everything else stays the same:intake, carb, stock dual snorkel air cleaner assembly etc. best Dyno pull was 233 RWHP with the stock motor and weak #6 cylinder. Hoping for 325 RWHP with the heads and roller cam. That would be at least 375 Net HP and over 400 Gross HP.

So a crate ( most crate engines are rated at GROSS HP) ZZ4 rated at 355 GROSS (NOT NET, NOT RWHP) HP for $5,000, roughly, is not a tremendous deal, although there are many other benefits besides HP. The AFR 180 heads and Howard's Roller cam along with gaskets, pushrods etc is going to cost me about $2,500 for me to do the work, all the name of keeping it a 1978 L-82. Just my 2 cents.

 

jb,
You have a great point there...it's a good 2 cents!
I'm also in a MOPAR forum, individuals with Hemis (me) A-12s, Max Wedge engines etc.
Option 1: Run your original engine, build it up to a more ROBUST build
or
Option 2: Pull the highly prized engine, store in a safe place and runa "Build-up" or crate motor henceforth protecting your original investment.
YUP, L-82s are not L-88s....LOL, wish we all had L-88s!
But it is only and option (crate motor) It is a viable and good option and the price is right. Hey! GM rngineering built it!

Thanks jb78L-82 for pointing this out!
Cheers!
"Super-bee_ski"

 

Hi Bee,

It's a ZZ4, not a Z4.

jb78-l82 pretty much hit the nail on the head; the performance is not there. It's a good choice for someone who wants an out of the box solution, but it's not going to be a real screamer. An L-82 with AFR heads and no other changes would actually be quite a bit faster than a ZZ4 - of course you're left with the bottom end of the motor in whatever condition it's in.

What you do get in the ZZ4 is not particularly great: L98 heads, a very mild roller cam (204/207 I believe), pink rods, hypereutectic pistons and a dual plane intake.

If you live in an emissions state, the heads do not provide an exhaust path so the EGR valve on the motor is actually not functional without adding an exhaust feed back into the intake. (it's definitely been done, probably easy to do with the heat riser port)

 

Thanks for all the input guys. I had a feeling the smog era heads were to blame and I know I will have to do a rebuild on the engine because it needs new seals and such thats why I was looking for some info regarding heads. I will say as far as cams go when I had it going I noticed the power band started around the 2500 range and I know for a fact the tranny hasn't been touched at all needless to say thats why its getting yanked rebuilt and sold. But the car did have true duals on it when I got it but I was always under the impression that a bigger exhaust would give me more flow and better horsepower, am I wrong in my thought process? Or does the 2.5 duals provide more back pressure than sidepipes ? Oh and I have already looked at crate motors and while it would be something to do later I just think the money with that is better spent elsewhere on the car right now.

 

Just a thought Recon but if that tranny is original to the car why sell it, someone down the road (if you decide to sell it), may give you more for the car with original tranny.... Like i said just a thought

 

yea its just a thought silva i know theres a short track and people race all the time on it so im pretty sure a rebuilt turbo 350 would fetch a pretty penny but yea i have thought about keeping all the original pieces except i would run outta room to keep them lol

 

Thanks Sharkracer!
I think it is a good "start"
The ZZ4 (Sorry for the mistake Z4...it's a BMW ...LOL)
GM lists it as:
355HP @ 5,250
405 ft~lb @ 3,500
Yes, torque torque torque!! AND, down low!
Anyway,
IMO, it's the best deal out there...!
Start w/ that and go any direction "one wants".
It's good enough for my builds.]
AND: "one" can save their original engine.
I'm not into the RACE engines.
It's ALL what the individual wants.
That IS what makes this FORUM so great. Acceptance of diversity.
Okay...keep up the great input!
Thanks man!