Hi All,

I've been lurking on the boards for quite some time now trying to learn as much as I can about 3rd Gen F-Bodies. I've always been a fan of the Firebirds, and recently inherited one from my brother.

It's an 83 Trans Am, "supposedly" with an '84 L69 engine that was swapped in, though the VIN shows it originally came with a LG4.

The engine is covered with years and years of oil, and is leaking from almost every conceivable place it seems. I haven't gone through the engine bay thoroughly but suspect I may have to pull the engine despite having healthy revs.

I was considering just rebuilding this engine, but if the engine needs to come out, why not entertain other options?

What option would be the most cost effective? Mind you, I live in CA and have to deal with smog.

- Swap out the block with a ZZ4 350 (assuming this is CARB legal or similar enough to the 305 that smog checks would be the same)
- Swap in the popular LSx engine

The ZZ4 350 seems like it would be less hassle with almost all the parts being swappable from the 305, though a weak point would be the stock T-5 Transmission.

The LSx seems ideal for everything is, with more and more swaps being more frequent. Not to mention all the bolt on pieces available now (k-member, transmission cross member etc). Though this swap requires additional leg work, sourcing additional parts, additional labor costs and wiring, not to mention getting it inspected at the referee center.

I'm getting the car repainted as soon as I get a game plan set, but this is how she looks right now:



I know L69s had an electric fan, but this ones got a clutch fan setup. Is there a way to determine if it's a L69? I found these numbers on the front passenger side of the block "V1010SXB", and below it "2EL24..." the rest was unreadable.

Any thoughts, feedback, comments welcome!

Regards,

 

Welcome aboard thirdgen.org.

Ah, California. Introduces all sorts of issues.

Best bet is to use an engine that looks identical to what came in it. You can do that with 350's and even a 383. But, you need to keep the computer controlled carb for sure, or use a later model EFI.

The ZZ4 has aluminum heads and no exhaust cross-over for the EGR valve. GM had a conversion kit several years ago that used the ZZ4, but it is no longer available. The C.A.R.B. sticker that came with the kit is one valuable piece that is no longer available. You might be able to sneak through if you painted the heads (center bolt valve covers would still be a give-away to a savvy inspector). But, if they do an EGR valve functional check (applying vacuum directly to the valve while idling, will kill the engine if the EGR valve is working), you'd fail unless you plumbed exhaust up to the intake manifold - and, if you plumb exhaust up to the intake manifold, it won't look like a stock installation.

You can do the ZZ4 and call it an '86-1/2 & up Corvette TPI. You'd have to swap in the TPI system, of course. That can be built with all emissions-legal equipment for decent performance and a clean sniff test.

You can do an LS1 by going through the "motor change" process. But, you'll have to include all of the LS1 emissions equipment, which includes the gas tank and its evap system. Might not sound like a big deal, but the evap needs fuel level input, and you can't use the 4th gen fuel level sender with a 3rd gen fuel gage - you'd have to swap in the 4th gen dash as well. Plus the usual stuff like catalytic converters, etc. Do-able, but involved.

Rebuilding the 305 would be completely legal, but pretty ho-hum. You can improve 305 performance in an emissions-legal manner, though - cam, headers, exhaust, intake manifold, head porting, etc.

The L69 should have a dual snorkel air cleaner and larger exhaust than the original LG4. If it doesn't have those, you might have gotten an L69 long block (only differences being the cam and higher compression between it and an LG4 long block), but you didn't get the whole enchilada.

 

Great information Five7Kid... Seems like the least path of resistance would be to either rebuild the 305 with better goodies, or safe up some serious penny for an LSx swap.

Good stuff, thanks for the feedback!

 

A 350 isn't out of the question. The full size B-body cars (Caprice, Roadmaster, etc.) had carb'd 350's in them from '83 (oldest year allowable since your chassis is an '83) to '87. So, put the 350 in with your carb et al, upgrade the exhaust, head for inspection. If they say anything, just tell them it came from a Caprice.

 

It's amazing how many cars had used the same block design in the same or similar fashion. I often forget about other options like this.

Before I start researching more about those models, is there a particular model you would recommend for a swap, or would it matter? Knowing my luck they (Referee Center) will question me about anything shiny in the car or anything that isn't black.

 

The fewer things to catch the eye, the better, in my opinion. If it looks like a 305, sounds like a 305 (doesn't have to run like a 305), and sniffs as clean as a 305, you'll never see the referee station. Besides, a referee station doesn't handle a motor change.

 

Very true about the bling stuff. Since this is a restomod for me, I'm going to marinate on this decision for a bit. The car had major oil leaks for a while, so I need to get it cleaned up anyways. After I get it steam cleaned, I can find out exactly what needs to be done to the block and base my decision then. Compression seems to be good at the very least, so I may very well just stick with this engine.

I read somewhere on the forum that with proper tuning the LG4/L69s with bolt ons can muster around 290rwhp? Not too shabby considering the stock output was around 150-190hp.

Thanks again for the valuable input Five7Kid. I look forward to learning more on the forum as I progress through this restoration.

 

Leaks can generally be fixed without major effort or expense. If compression is good, you can do a lot without paying a machine shop.

290 emissions legal HP measured the same way as the 150-190 were measured is a big challenge with a 305. But, you can substantially improve the way it runs.

Exhaust improvements are a must. Edelbrock is the only maker of technically legal VIN G headers. High flow direct fit replacement cat and 3" cat back system will help with everything else you do.

Comp, Crane, Lunati, others make computer-compatible cams that will be a substantial improvement over stock. Figure on needing new valve springs as well. Do the valve stem seals while you've got the valve springs off. While the intake is off for the cam change, put on an Edelbrock Performer EGR intake.

 

Kid,
From the Ca Air Resources Board:
"After an engine change, vehicles must first be inspected by a state referee station. The vehicle will be inspected to ensure that all the equipment required is in place, and vehicle will be emissions tested subject to the specifications of the installed engine."

The referee then puts a sticker in the driverside door jamb so future smog techs know what vehicle requirements to test for.

 

Didn't want to confuse this with the failure referee situation.

 

Say Five7kid... I know there's a lot of different options when putting together a block, but if I were to go the route of swapping in 350 doubling as a 305 like you mentioned... Would it be feasible to build up a 350 of the same generation using parts for the LG4/L69 (heads and intake manifold, quadrajet carb and headers)? Despite using the LG4/L69 stuff, I would imagine it would make more power than the LG4/L69 with bolt on mods. If so, I'd probably go that route using performance LG4/L69 pieces.

 

It's been a while since I've read up on SMOG regulations... The referee station deals with both engine changes and SMOG station escalations, right? Or are there different types of referees?

 

Yes. The LG4/L69 heads differed from 350 heads only in chamber and intake valve size. You can put the bigger 1.94" intake valves in the 350 heads, and with pistons with 11-12cc dish/valve reliefs, you'll have the same compression as with flat top 350 heads. It'll run fine (maybe even slightly better than the same engine with 350 heads).