Good afternoon all
I am unsure if I want to build a custom engine for my 92 Firebird or if I should get a pre-built one that produces the output I am looking for. I want to produce over 600 but I am not opposed to going higher. For a custom built one, I do not know where to start looking for a good platform to start from. I want to ensure that all components work together flawlessly. As for the prebuilt one, I am not sure whether there are benefits to a pre-built engine or a custom. I have mechanical knowledge and enjoy working with my hands so if I can I will do the work myself. I plan on replacing many other parts in the vehicle(transmission, differential) to work well with the new engine. I am willing to take any advice into consideration I have the time and plan on keeping this 92 for quite some time so I plan on spending a good chunk of money to get it where I want it.
Where do I start my engine building process? What kind of engine should I put in?

 

454 lsx from Texas speed

 

I have looked into that and that will probably be what I do. What about the 502 would there be any issues the only thing I have found is maybe the engine mounts but other than that nothing else has come up.

 

You want an LS swap kit which gives you the mounts, oil pan and headers for the 3rd gen. Then you need the wiring harness, ecu and a stronger fuel system. Then it's a matter of figuring out the trans. The engine is actually the easiest part of the puzzle.

 

Getting a fully built engine from a vendor like Texas speed saves you time of having to piece something together,comes with a warranty and for the most part you can still have custom things done to it if you want a different cam/heads etc. so call around to vendors and dive deeper into specs for the intended application. Like bammax said..the engine is the easy part of build. Making everything else work to support it is where you will need time,more money,patience,more money,planning..and more money.

 

I can look into Texas speed some more for a fully built engine. Where would I find a quality LS swap kit?

 

Not exactly a full kit, but Holley/Hooker has most of the parts for the swap, and they fit and work together. A good track record.

 

Ok, I will start there when looking for the swap pieces. So far what I have found going through forums is that both a 454 and a 502 will fit with some modifications. I have time and plan on putting in quality parts for this build.

 

A Chevy big block will bolt into wherever a small block went. Same mounts, same bellhousings. Only limited by space/weight considerations. And fuel consumption....

 

Sounds like you're talking about GM big blocks.

I would do the 454 LSX to save a ton of weight and size which makes swaps easier and the obvious benefits of being smaller and lighter.

Out of curiosity have you built the rest of the car for that much motor? I don't want to make assumptions but a lot of people want to throw the most power they can at a car without considering the rest of the build. Make sure that you are keeping the entire rest of the build in mind, depending if you choose an LS series engine or a big block, things will change. like suspension setups etc. The LS engine will make things a bit easier since it's so much closer to the size and weight of the original motor.

 

https://www.hawksmotorsports.com/82-...tory-k-member/

This is a pretty complete kit for a 3rdgen to swap in a lsx. They have everything you would need. Its pricey but 1 stop shop if that's what your looking for. You can piece things together much cheaper if you do some searching.

 

If you go LS the cubic inches have no bearing on the actual size of the engine or what accessories and such you need. It's nothing like the old days. You can go from 292 to 454ci without being able to see a difference externally.

 

Does a BBC with aluminum heads really save any weight compared to an iron block LS?

 

No. BBC iron blocks are far heavier than LS iron blocks

 

FWIW - My 91 RS had a full restoration & LS swap. I'd also planned and budgeted another for my 91 RS convertible.

It takes a lot of time to do correctly too or have done correctly. It's not a project for the faint of heart. It's also well worth when completed in my experience.

Most important part of the project will what is your budget.
Second most important part is do you love that Firebird.

Killer custom engine $8,000 to $16,000. 600 flywheel & 500+ whp is doable for ~$10,000

Get a great shop to do the engine if possible. Saves the and learning you didn't set preload correctly on the rockers and your new LS 427 has issues will suck. Thompson Motorsports has a great reputation. Bischoff Engine Service, Lingenfelter are renowned. Most LS1TECH sponsors do excellent work.

Superchargers are nice and easy way to make 800 hp flywheel and 700 whp $5000+

Tuning $500 to $1,000 for extreme set ups

Built 4L60e Transmission, torque converter, cooler & drive $4,000 to $5000

Built T56, clutch, drive shaft, new master, slave etc $4,000

Magnum T56 ( best choice in my experience), clutch, slave master, drive shaft $5000 to $8000 carbon fiber rocks

Built rear end, 9 inch or 8.8 or dana60, MWC aluminum housing tabbed 9 inch - $3,000 to $5000

Stock rear - free to $550 for a take out, it's a time bomb if you make power and get wheel hop...

Suspension - Subframes, savings, shocks, struts, chrome moly k member & arms, sway bars, RLCA's, Panhard, watts link, strut tower brace, etc $1,500 stockist to $4,500 with lots of aftermarket

Cooling - radiator & fans, stock $300 aftermarket $1,000

Wiring harness - $free to $1,200 depending on who does it

Fuel system - New high pressure set up for ~60 pounds of fuel pressure, regulator, fuel injectors $1,000 to $1,500

Brakes - atcleast 12 inch aftermarket Baer or better front & rear $2,000 and up to $3,500

Exhaust - 1 7/8 headers at least, y or x pipe, catback $1,000 to $3,000

Paint engine compartment $100 to $1000 professional

Paint car $1,500 low end to $5,000 typically good quality to $8000+ - New windshield look best $250

Aftermarket hood $600 to $850 for hood and $600 to make it fit right and fill imperfections on the underside and paint underside. Say $1200 to $1800

Body work $50 to $20,000 depending on if rust is present

Interior - hinge pins for doors maybe hinges too, weather stripping, seats, recover seats, dash pad -all typically minimum needs for a 3rd Gen - $2,000 to $4,000

Tire $600 to $1500

Wheels $500 to $5000


Hawk's Motorsports did my car. The car is stock reliable and I take the car on 1,300 miles trips on occassion.

It was well worth it and i would have it all done again


BTW - If one wants a 3rd Gen to handle like a pig, putting a BBC in the nose and adding weight will definitely do that.