The cars I am swapping...

1. 90 Formula, auto, 305, L03, TBI, stock exhaust manifolds and Y Pipe.
2. 87 Formula, auto, 305, LG4, Carb, stock exhaust manifolds, Y Pipe and T-Tops.

I am swapping the engine, rear end, exhaust (Cat back) and interior from the 90 to the 87. I have been told that I can take the intake and TBI off the 90 engine, then put the intake and carb from the 87 engine onto the 90 engine, then the 90 engine would work perfectly fine in the 87. All the while using either distributor because as I looked them up for both cars on auto parts sites they both use the same one.

I have decided that when I do this swap I am going to take this opportunity to add headers and a new Y pipe to the 90 engine going into the 87. Being that I already removed the Cat and I do not need to pass emissions inspections where I am located, I have also decided to take off all the smog equipment.

So, I have 2 questions.

1. I want Shorty headers, ceramic coated, no smog equipment and a Y pipe. The Y pipe can come with the headers or be purchased separately. Can anyone recommend a good setup for less than $510.00
2. One person had recently told me that once I remove all of the smog equipment I can remove the computer because that's all it was there for on the 87, just emissions control. But this doesn't sound right to me because isn't the distributor and the transmission and a lot of other stuff controlled by the computer?

Any help in this would be greatly appreciated. Please don't try to talk me out of doing the swap or using headers. My mind is made up on that and you'll just be wasting your time. And I only want to remove the smog garbage if it's not going to cause major problems with the car. My problem here is I know more about this stuff with older cars I used to work on, like my old 68 Firebird, 78 Formula, 69 Chevelle... No computers :-)


Thanks

 

Welcome to thirdgen.org.

You didn't say why you were doing this, but basically what you are contemplating will work. One caveat would be that the '90 engine would be a downgrade from the '87 engine, most everything being equal except for the heads. With headers and a cam change, the '87 engine would outperform the '90 engine with the same headers, '87 induction, and cam change. Unless the '87 engine is worn out or has a ventilated block.

You are right that the computer needs to remain in place. The "smog garbage" you speak of doesn't really reduce performance, although removing things such as the A.I.R. system will free up a little room.

Which accessory system were you planning on using, the '87 or '90? The '90 would be a little cleaner.

About the only headers out there ceramic coated for that price would be Hedman or Hooker shorties with their respective 2-1/2" y-pipe. Better than stock, but not as good as the Hooker 2055HKR's - which are certainly pricier. The problem with most commercially-available headers is the y-pipe - 2-1/2" after the "Y". The only exception is the Hooker 2055HKR's. There are other possibilities, such as member Dyno Don's custom made headers, but as far as I know, he uses 1-3/4" primary tubes, which are too large for a 305 (and from what I understand, more expensive than $510).

 

The reason why? I love my car. It is my favorite. But I always say I wish I had t-tops. And I know that down the road after they go classic for a while it's worth more.

The 90 engine is a serpentine belt setup by the way. And it has about 80k mile less on it. I have done quite a bit of work on it over the last couple years I've owned it and I trust it 100%. I know the engine to well. The 87? I know it has 260k miles on it and it does run good, but I have only had it a couple months. The oil pan is dented (big) and the exhaust leaks from a busted bolt I can't reach.

As for accessory? I am bringing over the entire 90 interior, dash, gauges and all. I like the 90 dash and door plastics better. Plus the 87 interior is destroyed.

So if I do remove the smog equipment but leave the computer, how can I do it and not upset the computer? Like will it just make the engine light come on and everything will run fine? Or will the car run bad because the computer see's that stuff is missing?

 

High mileage engine - makes sense.

You can remove the A.I.R. equipment and the computer won't care. You can remove the EGR valve as long as you keep the EGR solenoid, and the computer won't care. (Ask me how I know about those two.) Removing the A.I.R. pump will involve extra work (search on "smog pump delete) with the serpentine system. Nothing else really qualifies as "smog garbage", as it fits into the "control system" box.

The weak points of the '90 engine are the heads, cam, and exhaust. You're only taking care of one of those three with what you have planned. Exhaust is "necessary", but not necessarily sufficient.

Not that it won't run well, it just won't run as well as it could. The difference cam, heads, and exhaust makes is amazing. Oh, and air cleaner improvement - neither the LO3 or LG4 air cleaner is that great with their single snorkel.

 

I saw that article about using a different belt and re-routing it to make it work. I will definitely be doing that. The air cleaner I have on the 90 that is coming with it to the 87 is a chrome open air cleaner with a K&N. It made a huge difference.

I have the opportunity to use the heads from the 87 engine on the 90. But will they work together? And what are the differences between the heads on both engines?

Thanks for all the info so far.

 

The difference between the heads is the '90 heads are "swirl port" - they have a wall in the intake port that directs the air flow in such a fashion that it swirls into the combustion chamber when the intake valve is open. Works fine for better economy and somewhat lower emissions on a low performance engine, but limits performance pretty rapidly when you make upgrades.

The '87 heads will bolt in place of the '90 heads. You may have to keep the '87 rocker arms - I'm unclear whether they went to self-aligning rocker arms in '87 or '88, but I believe it was '88. You can tell by the size of the rocker arm hole in the head - if it is round, you need self-aligning rockers. If it is oval and just barely wider than the pushrod, you need non-self aligning rockers.

 

Oh and sorry, when you asked which accessory system, you meant engine accessory huh? I am keeping the 90 engine accessories. The only things from the 87 engine I am reusing is the intake, carb and starter as the starter is new.

 

As stated above, please do yourself a favor and replace the heads with the 87 LG4 pieces. Rebuild them, ensure you have 1.94" intakes, and then enjoy the benefits of that. Your TBI heads will restrict your engine and actually take your carburetor setup backwards in terms of performance. Your roller cam is about the same, but now would be a good time to upgrade to a later TPI or LT1 cam (used of course) to pick up a little pep. Your TBI "peanut" cam is bad like your heads fo performance.

 

You said you cant get the exhaust bolt. Well if you drop the exhaust from the manifolds and then the bracket from the back of the transmission and you will have easy reach. And i know because i have a 87 LG4(Carb'd 305) same engine so i know it can be done(did it last month).

 

Well I took the easy way out, I paid someone else $800 to swap the engine and I just got it back today. They took the 90 engine and re-gasket the entire thing, put on a new Edelbrock Performer RPM intake, took off all smog equipment and put on new Flowtech painted headers. The carb is crap so I ordered an Edelbrock Performer 600, it will go on the car this Wednesday. As a trade, I will be giving the old 87 engine to the guy who did the swap and he will swap over all the front and rear suspension.

As of now, the car sounds much better and it is much quicker than the 90 was, this one has a recently rebuilt transmission. My wife said it sounds louder and less muffled. She said it sounds more open. All just because of the headers :-) The open air cleaner will not fit on this car like it was in the 90 because of the taller intake. So I am going to get a new one with a K&N 10"x2" filter. Anyone need an Edelbrock chrome cleaner with a K&N 14"x3"? It's in the pic above, less than a year old.

I started getting a few things off the 90 this evening that I needed on the 87, like my license plate, tail light bulbs, rear latch, etc... But then I noticed the 87 has rear lap belts, the 90 has shoulder belts. So I may do the mod I found on here about making shoulder belts for the early 3rd gens.

That's all for now. I'll post a pic of it tomorrow.

Oh yeah, we had a hard time getting the right intake, because as it turns out the 90 engine has Vortec heads on it. HA! I love it, someone put them on before I bought the car a couple years ago.

 

More than likely, you still have the crappy LO3 heads. The 87 and up have a different intake pattern than the 86 and older heads and the older intakes don't fit. Unless your intake bolts are straight up and down, they're not Vortec.

You should have kept the 87 LG4 heads, they use the same weird intake and they're much better for performance.

 

All bolts straight up and down or just the two in the middle? On mine they are the two in the middle, the rest are slanted.

 

The 87 with the 90 engine. The 87 engine had the multiple belt driven system, this one has the serpentine. Already the engine looks better in this car with the cleaner accessory setup. I still have quite a bit to do to the car.

 

All bolts straight up and down, and no bolts in the middle (only the corners).

Doesn't sound like you have "Vortec" heads. Sound like standard '87-up heads, and if TBI, probably swirlports. Casting numbers is the only way to know exactly what you've got.

 

Those are your standard heads from 87-up. If you still have your 87 engine, keep the heads. When you get the money, have them rebuilt and put them on your engine. They are great for what you have and also good for a 350 build up in the future.

Your heads are good for efficiency but not power.

 

Cool, thanks. I was just relaying what the guy that did all the work said. He did a great job but I can tell he doesn't know firebirds much. He also said both engines are H.O., and that you can tell because they both have roller cams and they only put them in H.O. engines. I had to explain and correct him on that but I think he still thinks they are H.O.

Oh well.

 

LO3's in f-bodies all had roller lifters. As did '87 LG4. That hardly made them "HO".

 

I explained to him how in 87 they started putting rollers in all v8's but not all of them were HO, I don't think he bought that. Whatever, he did a great job and it's been me picking out all the parts. So at least he's not getting the wrong stuff thinking the engine is one thing and it's really another.