New User 83 Grand Prix

[83GPLJ]

Hi all I have recently acquired a 1983 Pontiac Grand Prix Lj 28th the 3.8 v6 from a family member. The engine needs a head gasket and I want to do a v8 swap. I've been researching the lsx swap and I've decided if I go that route I'll do a carb 5.3 and a 4l60e(maybe) and I'll probably need a new rear end.

The 5.3 swap will probably run me 5-6 grand.

As a cheaper route i was researching 350 swaps. The sbb 350 would bolt up but they're not as cheap or plentiful as a and 350. So I can do a carb Chevy 350 with a th350 or 700r4 and probably keep the rear end? What do you guys think that would run me?

 

[454GrandPrix]

The SBC is the cheapest, easiest V8 engine to build, rebuild or modify. You can go as mild or as wild as you like--the sky is the limit. Simply change your motor mounts and it'll drop right into your engine bay.

Can you keep your rear end with a V8 swap. Sure, you can. The question is, how long will it last? That depends how much torque you feed it, how abusive you treat it, whether or not you use slicks, etc.

The turbo 350 trans may be a bolt-in swap for your car depending on what trans is in there now. Worst case, you may need to swap crossmembers. But even that would be a simple, bolt-in affair.

HTH

 

[Texas82GP]

There is a small block Buick for sale in the Classified section......
https://gbodyforum.com/threads/1975-pontiac-400-engine-and-1975-buick-350-engine.61644/
Depending on where you are, it should be possible to strap it to a pallet and ship it truck freight for less than $500. If you get serious about it, contact a freight broker or two to get a good price.

There are lots of ways to do the small block Chevy. Find a good Vortec, swap in a cam, springs and retainers, a Vortec 4-barrel intake and headers for an inexpensive 350-400 HP. Or rebuild the Vortec while you are at it. Or buy a crate engine. Or find some other SBC for sale. It depends mostly on budget.

I bought a 350hp 350 from Pace Performance two years ago. I think I spent around $2300 but I'd have to look it up. It's a Goodwrench shortblock with Vortec heads and a mild performance cam. No intake.

Keep in mind with the SBC you will need a different front accessory drive, so that factors in on budget.

What transmission is in the car now?

As far as the rear end, my suggestion is get the car running now and enjoy it. Upgrade the rear end later. Depending on your power goals and how you intend to drive the car. The 7.5 may be fine. If you aren't going to run slicks and abuse it, you could budget upgrade it with a torsen limited slip differential out of a fourth gen Camaro and new 28 spline Moser axles.

If you plan on more power than 350-400 hp, you need to seriously consider stiffening up the frame and will need to upgrade thd rear to an 8.5, 8.8 or 9".

 

[83GPLJ]

The SBC is the cheapest, easiest V8 engine to build, rebuild or modify. You can go as mild or as wild as you like--the sky is the limit. Simply change your motor mounts and it'll drop right into your engine bay.

Can you keep your rear end with a V8 swap. Sure, you can. The question is, how long will it last? That depends how much torque you feed it, how abusive you treat it, whether or not you use slicks, etc.

The turbo 350 trans may be a bolt-in swap for your car depending on what trans is in there now. Worst case, you may need to swap crossmembers. But even that would be a simple, bolt-in affair.

HTH

Yes that's exactly what I was thinking. Just swap cross members and be golden. Then I would just need to have a driveshaft made. Thank you for the advice.

Devin

 

[83GPLJ]

There is a small block Buick for sale in the Classified section......
https://gbodyforum.com/threads/1975-pontiac-400-engine-and-1975-buick-350-engine.61644/
Depending on where you are, it should be possible to strap it to a pallet and ship it truck freight for less than $500. If you get serious about it, contact a freight broker or two to get a good price.

There are lots of ways to do the small block Chevy. Find a good Vortec, swap in a cam, springs and retainers, a Vortec 4-barrel intake and headers for an inexpensive 350-400 HP. Or rebuild the Vortec while you are at it. Or buy a crate engine. Or find some other SBC for sale. It depends mostly on budget.

I bought a 350hp 350 from Pace Performance two years ago. I think I spent around $2300 but I'd have to look it up. It's a Goodwrench shortblock with Vortec heads and a mild performance cam. No intake.

Keep in mind with the SBC you will need a different front accessory drive, so that factors in on budget.

What transmission is in the car now?

As far as the rear end, my suggestion is get the car running now and enjoy it. Upgrade the rear end later. Depending on your power goals and how you intend to drive the car. The 7.5 may be fine. If you aren't going to run slicks and abuse it, you could budget upgrade it with a torsen limited slip differential out of a fourth gen Camaro and new 28 spline Moser axles.

If you plan on more power than 350-400 hp, you need to seriously consider stiffening up the frame and will need to upgrade thd rear to an 8.5, 8.8 or 9".

I don't plan on making more than 300hp yet. I was thinking a junkyard 350 out of a truck and putting vortec heads on it. Then maybe a cam and lifters and a performer rpm intake and a 4 barrel carb.

The trans is a 200-4r or whatever the "200..." Trans that came with the v6 cars.

The rear end I figure I can get away with for a while because it would be a weekend driver with normal street tired on it. I looked into a 9" rear for gbodys and it runs about 2 grand. I guess I can do an 8.8" out of an explorer? I remember seeing a thread about welding the cars spring perches on and it would work?

 

[454GrandPrix]

There are lots of ways to do the small block Chevy.

This is so true. Don't let anybody tell you that a SBC must be done "their" way.

I bought a 350hp 350 from Pace Performance two years ago. I think I spent around $2300 but I'd have to look it up. It's a Goodwrench shortblock with Vortec heads and a mild performance cam.

It sounds like the OP already knows this, but the factory iron Vortec heads are a great value for the dollar. Off the shelf (or out of the junkyard), they work well. A small amount of machining to allow larger valve lift makes them work even better. Had I gone with a small block rather than a big block, that's what I would have done.

Keep in mind with the SBC you will need a different front accessory drive

Oh, yeah. I ran into the same issue swapping from my 231 to the 454. My donor engine was a Vortec, meaning a serpentine setup that I didn't want to use for a number of reasons. I scouted wrecking yards until I found a 1979 pickup with a 454, and I scavenged its brackets and v-belt pulleys to put on my engine. My only other option was to buy fancy new aftermarket pulleys and brackets, which tend to be a bit costly.

Yes that's exactly what I was thinking. Just swap cross members and be golden.

The trans is a 200-4r or whatever the "200..." Trans that came with the v6 cars.

Oh, wait, your car is an '83 and thus pre-dates the 4spd transmission. In your case, the Turbo 350 is a direct bolt-in. Considering your desired power level, I'd say that is a great way to go. If you want to use a later 4spd transmission, then you'll need to change crossmembers... and on your 1983, that will require installing a frame extension, which means you'll need to drill two holes. (It's still a simple operation; I mention all this merely in the interest of full disclosure.)

I guess I can do an 8.8" out of an explorer?

If you're gonna install an 8.8, get one out of a Fox body Mustang. It is the easiest to install. Yes, you'll need different axles to change your wheel bolt pattern (which I haven't done yet, as you can see in the photo below), but that's simple enough.

 

[Texas82GP]

I don't plan on making more than 300hp yet. I was thinking a junkyard 350 out of a truck and putting vortec heads on it. Then maybe a cam and lifters and a performer rpm intake and a 4 barrel carb.

The trans is a 200-4r or whatever the "200..." Trans that came with the v6 cars.

The rear end I figure I can get away with for a while because it would be a weekend driver with normal street tired on it. I looked into a 9" rear for gbodys and it runs about 2 grand. I guess I can do an 8.8" out of an explorer? I remember seeing a thread about welding the cars spring perches on and it would work?

In that case, try to find a good Vortec long block. It's real popular to put something like the ZZ4 cam or LT4 cam or an aftermarket cam, replace the valve springs with beehive springs and the Comp Cams retainers (part numbers in the thread below - see post 24 by Bar50) for clearence on the Vortec valve guides and seals with higher lift. With a 4 barrel carb and dual exhaust you will be easily over your 300hp goal. You could use the accessory drive off the Vortec engine, or off of an 89-95 truck, or off the third gen Camaro to keep it on a budget.
https://gbodyforum.com/threads/junkyard-vortec.61639/page-3

 

[83GPLJ]

In that case, try to find a good Vortec long block. It's real popular to put something like the ZZ4 cam or LT4 cam or an aftermarket cam, replace the valve springs with beehive springs and the Comp Cams retainers (part numbers in the thread below - see post 24 by Bar50) for clearence on the Vortec valve guides and seals with higher lift. With a 4 barrel carb and dual exhaust you will be easily over your 300hp goal. You could use the accessory drive off the Vortec engine, or off of an 89-95 truck, or off the third gen Camaro to keep it on a budget.
https://gbodyforum.com/threads/junkyard-vortec.61639/page-3

Yes i was planning on trying and getting a 95 or earlier 350 and putting vortec heads on it or maybe I can get a 96-99 vortec 350 and swap it to carb. Thank you for the cam advice as well. I didn't realize I would be able to break 300hp that easily

Devin

 

[Texas82GP]

Yes i was planning on trying and getting a 95 or earlier 350 and putting vortec heads on it or maybe I can get a 96-99 vortec 350 and swap it to carb. Thank you for the cam advice as well. I didn't realize I would be able to break 300hp that easily

Devin

One thing I didn't mention is the Vortec engine isn't drilled for a mechanical fuel pump so keep that in mind. You could run an electric pump and still go carb though.

 

[83GPLJ]

This is so true. Don't let anybody tell you that a SBC must be done "their" way.



It sounds like the OP already knows this, but the factory iron Vortec heads are a great value for the dollar. Off the shelf (or out of the junkyard), they work well. A small amount of machining to allow larger valve lift makes them work even better. Had I gone with a small block rather than a big block, that's what I would have done.



Oh, yeah. I ran into the same issue swapping from my 231 to the 454. My donor engine was a Vortec, meaning a serpentine setup that I didn't want to use for a number of reasons. I scouted wrecking yards until I found a 1979 pickup with a 454, and I scavenged its brackets and v-belt pulleys to put on my engine. My only other option was to buy fancy new aftermarket pulleys and brackets, which tend to be a bit costly.





Oh, wait, your car is an '83 and thus pre-dates the 4spd transmission. In your case, the Turbo 350 is a direct bolt-in. Considering your desired power level, I'd say that is a great way to go. If you want to use a later 4spd transmission, then you'll need to change crossmembers... and on your 1983, that will require installing a frame extension, which means you'll need to drill two holes. (It's still a simple operation; I mention all this merely in the interest of full disclosure.)



If you're gonna install an 8.8, get one out of a Fox body Mustang. It is the easiest to install. Yes, you'll need different axles to change your wheel bolt pattern (which I haven't done yet, as you can see in the photo below), but that's simple enough.

Thank you for the advice on the sbc. I was planning on keeping it simple like I posted above and maybe re ringing it to ensure good compression and get a look at the bearings while I'm in there.

The trans news is perfect, Thank you. I'm glad it should bolt right in, that will make this much simpler and save me a few bucks.

For the rear end thank you again. I was reading that the mustang rear is better because it's closer to stock length.