I have a 1985 El Camino SS with the original 305 that I've had since I started driving. The problem is that the 305 has a little over 166,000 miles and it's starting to spit blue smoke and it's getting VERY weak. So instead of rebuilding the 305 I thought that I would pull it out and set it aside (since it's the original engine) and put something a little more exciting between the fenders.

I've wanted to give my SS a makeover for a while now. A few years ago I worked at a body shop and I gave her a new paint job, pearl white, and I also removed the bed rails and welded in and smoothed out the mounting holes. The cheap looking body side molding was also removed for a much cleaner overall look. But since this car is my daily driver, the elements and the hard miles have started to take a toll on the pearl white paint, the driveline, suspension...everything.

I figure that if I'm going to put a new engine in it I should go for a big block since I've always wanted one. I was particularly interested in the ZZ454 from GMPP, which is an aluminum headed 440hp 454...perfect. But my main question is...will the 454 fit between the fenders of my G-Body, which has every option under the hood, including AC? It'll be a while before I can afford to give my SS the kind of makeover that I want (and it deserves, after the years of 100% reliability), but I just wanted to get some input on the big block conversion ahead of time.

Thanks for any help!
Phillip

There have been many big block conversions into 5th Gens and while possible they are not without problems. The AC/heater box will have to go for clearance so you will have to forget about AC unless you use a compact aftermarket unit. I am a big fan of the Chevy Big Block and have owned many vehicles powered by BBs (have two right now) but I don't think that a 5th Gen really needs a Big Block. You can get upto 700 streetable horsepower in a small block today which was not even remotely possible 30 years ago when I made my first Big Block conversion. I just don't think the disadvantages overcome the advantages of a 5th Gen Big Block.

Thanks for the reply. I kind of figured that it would be a really right fit to get a big block in a G-body car. There's an article at Popular Mechanics in the "project cars" section that shows how they put a 454 in a 1984 (or so) Old Cutlass, and they actually kept the AC in the car somehow.

I was also looking at the ZZ383 small block crate engine, also from GMPP, which has 425hp right out of the crate...not to mention the warranty that comes with it ;) It also has aluminum heads to help get some weight out of the nose of the car.

With that much extra power the entire drivetrain will need to be upgraded. I'm thinking that my TH200R4 will need to be "Art Carr'ed" to handle that much horse power, similar to how the Turbo Buick guys have to build theirs to handle all that horsepower and torque from the turbocharged V6s. At any rate, I know the 200R4 can handle it when built properly...I'd really hate to give up overdrive or switch to another OD transmission. I would also like to get ahold of an 8.5-inch differential from a Turbo Buick to replace the 7.5-inch that came stock in the Chevy G-body cars. Driveshaft, exhaust, suspension and brake upgrades are also on the drawingboard.

I would also like to use some 17" x 8" American Racing Torq Thrust (or similar) wheels so I can put some really sticky rubber under the car to plant all that power better.

I also added a picture of my '85 SS to my profile...the picture was taken at a car show back in August of 2000, shortly after the new paint was applied.

Phillip

Your El Camino looks real nice and the plans for your Elky are pretty much the same as mine. Keeping the 200R4 is a good idea and upgrading the rear axle to a Buick GNX unit is very desirable but good luck in finding one as very few were ever made. I have 17X8 wheels with Nitto rubber and along with sway bars, shocks and bushings it made a big difference in handling. I think keeping a smallblock is a wise choice in keeping a balanced vehicle and avoiding some big problems with a big block. Good luck!

What is the backspacing on your 17x8 wheels and what size tires are you using? I'm having a hard time trying to figure out what fits. I've heard of 275s fitting, but right now I'm running 235s on 15" rally wheels and it's tight, but then again those sidewalls are quite a bit taller than the 17" tires would be.

For the differential I was thinking about using one out of a regular Turbo Regal or Grand National, since they don't require all the extra fittings that the GNX rear end and they'll also bolt right in. The GNX used a really wierd "latter bar" type thing along with extra braces, but there was a company that was making repro parts for them a while back...quite expensive though.

If I can't find a Turbo Buick rear end I could always look into the aftermarket 12-bolt rear ends that are being made specifically for G-bodies.

Phillip

I know someone who put a ZZ4 Motor in a 85 Monte Carlo and used a Art Carr 200R Transmission and it only lasted less than 1K miles and with the converter cost over $3000 so you might want to ask around about a Trans that will hold up.

Luckily the TH400 can be used with the TH200R4s crossmember ;) I think there was a company making overdrive units of some sort for the standard TH400.

Phillip

There's a guy around here with a 454 in his early 5th gen, and he has space to work in there too. Granted he stripped the engine compartment bare and just left fenders, but hey...any camino running 10's is just fine by me. :cool:

A BBC can be installed in a 5th gen, keeping the AC as long as you use short valve covers. The 200 trans won't hold up for long behind the torque of a big block. The GNX 8.5" rearend is the same as the GN or Regal Type T...it's the add on suspension pieces that make it more desireable...Kirban Performance makes the pieces for the GNX style rear suspension. A 68-72 Chevelle 12 bolt rear can be used (bolt in) with aftermarket trailing arms. 9" Ford bolt in rearends are readily available from a few different suppliers.