My 87 trans am broke a crank, originally a 305, swapped to 350 and kept original. I have another 350 out of a 91 tbi, and also have headers with the o2 sensor hole. Id like to keep everything but egr and possibly get a better intake while I'm doing the swap. Anyone with any experience that wanna chimes in will be appreciated.

 

Not completely sure what you're asking...

If you want to know if you can either use an intake without EGR provision at all or one that has it but block it off, then yes. The carb does not care.

 

I'm currently thinking about upgrading my intake on my carb 350 firebird as well.

 

Be aware that in a Firebird, the hood is VERY low, and there's VERY LITTLE room above the engine. So, as you "improve" the intake, which moves the carb upward, it gets closer to the underside of the hood. Of course this also moves the air cleaner upward. Since space is limited, it can only be raised just so much, before the AC lid hits the hood. Of course, you can get a "drop base" air cleaner, which sorta LOOKS LIKE it solves the problem, until you realize that in essence what that does, is that it maintains the air cleaner lid at a fixed height, and raises the carb up inside it, thus bringing the top of the carb closer to the underside of the AC, creating a restriction. And since the space there is already arguably too small, the loss in airflow due to that, can easily MORE THAN offset any "gain" from some "better" intake. Which on most engines, there's no gain from futzing with the intake ANYWAY, because the intake usually isn't The Bottleneck to the engine's performance to begin with. You can end up spending money to reduce engine output.

Choose wisely.

 

Exactly what Sofa said. I was going to post exactly what he said in my words.

 

Two unmentioned items for OP: an original 1991 TBI 350 has heads with intake ports that are heavily narrowed. They induce intake flow swirl, and are very poor for performance.

Deleting EGR with your combination of parts will increase combustion temperatures. EGR cools combustion temperatures, allowing for increased timing, which gives better part throttle performance and mileage.

I had dysfunctional EGR on an 87 4bbl. A new intake (Edelbrock for 87-up w/EGR) replaced an original with corroded coolant passages and clogged heat riser/EGR passages. Fixing it improved mileage and throttle performance because timing could be advanced more than without EGR function.

Degrade your vehicle all you want. If you have a functioning control system for the EGR, it's foolish to delete.

 

I am not opposed to keeping it, here's my project. Intake and carb from 87 305 on a tpi longblock. I believe im missing some linkage on the carb for the air valve. Its mostly there but not reinstalling the air pump as I have shorty headers for it. Trying to figure out where to find the linkage if im missing it.
I miss posted, its a tpi not a tbi.

 

You are indeed. Easy enough to find at the junkyard.

What head casting number does it have?

 

Its a 91 tpi, where are the numbers located?

 

Under the valve cover, in between some of the rockers.

 

Everything is torqued and about to go in. I do know the tpi heads had the same 4 intake manifold bolts with different angles.

 

So do ALL other 87-up cast-iron SBC heads including TBI ones (except 96-up Vortec). Which outnumber the TPI heads present in the world at large by probably AT LEAST 50 to 1. Not that I'm saying "they're not" TPI heads, only, that the odds are HEAVILY against it, unless you know the COMPLETE history of the engine.

Butt hay, sounds like at this point It Is What It Is, for better or worse, and you're not interested in knowing the truth with certainty. Which is OK; it's not like you could change it anyway, whether you know or not, without significant $$$ and effort.

 

Yea right now its just a push to get it running. Plan to build a engine later on.

 

It's going to be really easy for you to verify the casting numbers of the cylinder heads on your new engine when you remove the 1990 to 1992 speed density TPI center bolt valve covers and replace them with the center bolt valve covers that came on your 1987 LG4 engine.

Your carbureted engine will not work with the CCV/PCV grommet and oil filler locations on the 1990 to 1992 TPI center bolt valve covers. This assumes you are putting the engine back in using the stock air cleaner assembly and not doing something ignorant like running a open element air cleaner assembly. Our cars are little Easy Bake ovens under the hood. The last thing you want is to be doing is sucking up that hot under hood air into the carburetor. Since you are swapping out the cast iron manifolds for cheap thin gauge mild steel headers without a thermal barrier coating the Easy Bake oven is being upgraded to a Dutch oven.

If you play your cards right you will have an engine that will be a 5.7L version of the L69 5.0L H.O. engine and it will make about 100 more horsepower and 100 more foot-pounds of torque than the 170 HP 250 FT-LBS 1987 LG4 engine did.

If you rush into doing this engine swap mistakes will be made along the way and many things overlooked that will have to be addressed later on that would be much easier to do now while the engine is out of the car.

Just offhand these things will have to be changed if you want your engine conversion to work correctly.

You will need a different knock sensor and electronic spark control module. The ones from the LG4 engine won't be right for the L98 engine and the knock sensor in the block of a 1990 to 1992 L98 won't be right for the correct electronic spark control module you will need to use with your 1987 LG4 ECM.

Your car will need to be converted from a single wire unheated O2 sensor to a 4-wire heated O2 sensor because you are swapping from cast iron manifolds to headers and there will be so much heat loss in the exhaust system by the time you get to the O2 sensor, which will be much farther away than it was in the cast iron manifold, the O2 sensor won't be hot enough to work correctly.

The secondary metering rods and hanger assembly in the Q-jet carburetor are going to need to be swapped to a set that is richer.

The thermostat should be swapped from the stock LG4/L98 195 F unit to a 180 F unit and the cooling fan switch in the passenger side head between cylinders 2 and 4 should be swapped for one with lower set points to match the cooler thermostat.

And on, and on, and on.

 

Awesome info, unfortunately my car came with a 1985 engine, but the perimeter bolt valve covers have the correct holes for the breather and pcv for stock air cleaner. I will look for a stock valve cover set to replace the tpi set. Appreciate the knock sensor information as i was going to browse the manual i have about that. The o2 is interesting, will have to look into that swap as I want it to run correctly.

 

Oh, I didn't know it had an 85 spec 5.7L engine in it and not the 87 spec LG4 engine. The 87 LG4 is a one year only configuration for a F-body. It's basically a LB9 TPI automatic spec engine with a carburetor induction system instead of the TPI system.

Easiest center bolt valve covers for you to find to use are 1988 to 1992 F-body TBI or 1987 to 1989 F-body TPI. Everything is in the same location as on the 87 LG4 center bolt valve covers. There may be other applications with center bolt valve covers that fit.

 

I appreciate that information, it is originally a 305 carb from factory, someone swapped the older 350 in before I got it. Ill look for those valve covers.

 

"You will need a different knock sensor and electronic spark control module. The ones from the LG4 engine won't be right for the L98 engine and the knock sensor in the block of a 1990 to 1992 L98 won't be right for the correct electronic spark control module you will need to use with your 1987 LG4 ECM."

What electronic spark control would I use? I figured the one from the 87 305 would do. Same goes for knock semsor

 

I just checked in on this thread a few minutes ago to see if anything new was going on with your swap.

I'll post the instruction manual for GMPP Chevy Race Shop ZZ3/ZZ4 H.O. 350 Camaro engine conversion. Lots of good information in there. With part numbers. I think of it as a rough blueprint of how to swap a higher performance 5.7L engine in place of a Computer Command Control carberutor distributor LG4/L69 5.0L V8 with automatic transmission.

Give me a minute to find it and I'm steam cleaning my carpet too so I will be in and out.

Also does your car still have wiring and stuff for the knock sensor and Electronic Spark Control module? It's been swapped with and earlier engine and who knows what else has been done over the years.

 

Knock sensors are based on the engine block's bore diameter. So, a 305 sensor won't be calibrated for the 350's larger bore.

 

I was under the impression these guys just slapped a older long block in place of the 305 and retained the entire wiring and sensors and vacuum lines. They drilled the 4 intake manifold mounting holes to make it fit the older style heads. That thread would be super helpful and I would appreciate it when you get around to it.

 

Can you PM me your email address?

The forum has a 20MB file size limit on attachments and the information I want to send you is around 70MB.

 

Thanks again for the help. May have a co worker with some 1995 tbi truck valve covers but we'll see if the holes are in the right spots!