Hello, I am new to the site, new to the world of turbos, and new to the world of forums. I hope to take my 1988 Firebird from its current state of a very consistent (reliable) strip only car to a fun street/strip....with some boost.
A little history on the car. I purchased the Firebird a few months ago, although I have been around the car for 18 plus years. I have had a couple drag cars that were bracket raced mostly at our local 1/8th mile track. The Firebird was driven by an old gentleman- Barry - in street class......that consistently kicked everyone's ass on any given weekend. I got my start in street class, being schooled by the old man. We all would play the staging lane game of trying to not pair up next to him when it came time to pull into the burnout box. As well as being a deadly consistent bracket racer...he was a wealth of knowledge and stories. When he knew he could not race any longer due to health issues, he offered the car to a friend. My buddy probably paid too much for it at the time....but he didn't care. The car was put in storage, where it sat for several years after Barry passed away. About 3 years ago we were talking about our multiple projects that would never be finished, and the Firebird came up. He said he had thought about selling it to help fund another project. The plan was made for us to get it out, change fluids and take it to the track one last time. To be honest...that day was the most fun I have ever had at the track. I went several rounds in street class, car did its thing and I did mine, until the final round where I got a little too aggressive on the tree and went red. Car ran the number, and I was thrilled as could be with runner up.
Another close friend of ours and Barry heard the car was for sale, and quickly bought it. He has a GTO and rear engine dragster that he races, and the Firebird was going to be her bracket car. They completely went through the car, gave it a fresh 383 on alcohol, glide with trans brake, and a stout 9" rear and a 6 point cage. Car consistently ran. 6.60's and was very reliable. Well after a couple seasons of juggling 3 cars, two kids and 3 dogs at the track they decided to downsize. I was offered the car for a great price and jumped on it.
I am not a track only guy, so the Firebird will be put back on the street. I have been on the fence about what direction to go, but knew I wanted some kind of forced induction blow thru small block. I was about to pull the trigger on a F1a Procharger, when the thought of a turbo setup came up. The Procharger would of been the easy route...but that's not my style. So this is my from strip to street turbo build...

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Cool car! Lotta things you wanna think about. How much power you're looking to make, do you want to make that power with reliable and expensive parts, or the eBay China way? My guess is the 383 has a race cam and high cr Pistons- turbos don't need nearly as much cam and it'll be more streetable. You're also going to want static compression in 9 to 1 range, and of course a carb and fuel system capable of handling boost. Sounds like you're well on your way with whats in the car already, you could turn thing into a whole new animal!!

 

Current motor setup...383, 4 bolt block 4.030" bore, filled to freeze plugs, Howard's steel crank 3.75" stroke, RPM 6" rods, Ross dome pistons (12:1), gently massaged Brodix Track 1heads with Manley valves, Comp Cam solid roller 300/308, .630"/.630" cam and lifters, Harland Sharp 1.6 rockers. Single plane high-rise, 4150 alcohol carb. MSD billet distributor, ignition. Solid, reliable combo that ran consistent 6.60's 1/8th without killing parts.
Picture was taken just before I pulled it out and tore it down this weekend. New parts are starting to show up...boost friendly Carrillo dished pistons/rings, Comp Cams 12-704-8 solid roller, Cometic head gaskets, fresh bearings/oil pump/timing set. Decided to go with a ProSystems blow-through E85 carb, Aeromotive A1000 pump and boost reference 13202 regulator.
Heres where I am undecided........single s480 or twin s300's? I am leaning towards the twins.

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As far as hp goals... I would love right around 10 hp less than it takes to split my factory block lol. Realistically I would be happy with 850-900hp at 7,000 rpm max. Goals with the turbos would be to have boost ramping up around 3,500 if possible. The car was launching at 4,700 on the brake and 4.56 rear gear, 28x10.5 slicks. With the anticipated power, would like to start out coming out around 3,500-3,600. Will be on same size slicks, and at times 275/11.5 ET Street Radial Pros. Gear is still a toss up.....3.50 or 3.70??

 

Down pipes would be a lot easier with twins, those big pipes can be a bear to get out of the engine compartment without hacking a bunch of stuff up.

 

I just talked to a guy wanting to turbo his Firebird and directed him to this site. You wouldn't be the same guy would ya? Im Marty from Stromberger Performance.

 

No Marty it was not me, but nice to meet you. Actually on the exhaust issue....when the plan was Procharger, I made exhaust tunnels next to the trans tunnel(one big happy tunnel really). There is enough room to run dual 3" out with mufflers and dump before the axle. I fabbed up everything, welded some 3" stainless ball flange collectors on my Stainless Works headers, and tacked up the pipes. Lowest point for ground clearance was just under 3" going under the custom trans mount. The car sits fairly low, so that doesn't help matters any. Once that was all done I decided to go the turbo route lol. Plans now are to do twins and have the exhaust exit through bullet mufflers in front of each front tire-low location thru the fenders. If it's " too loud" by my standards, I know I will have the room to run out the back.

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One more interior pic. This was in race trim, I have since added the second seat and started putting the halo bar and down bars to finish the cage and get certified.

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Slow progress this past week, but did commit to twin turbo set up. Purchased two BW S300sx3, 60/68 with .91 a/r. Also went with two Tial 38mm gates and the 50mm bov. Bottom end is apart waiting on new pistons to show up. I would probably have better luck asking on another section, but what kind of rod/main clearance is recommended on turbo Sbc? Thanks in advance

 

Don't quote me but I've read about 3 thousandths of an inch on higher performance boosted builds to allow for crankshaft flex and other small imperfections/ differences in rods and bearings.

 

I just use stock clearances, the ring gap I calculate by multiplying the bore diameter by .00675. Never had any issues doing it this way.

 

my 383 has .0028 rod and .0030 mains .

..0065 or like hillbilly said .0067 x bore ......... and second ring slightly larger .

 

Thanks guys. Hey blown385, AWESOME truck! I have read your build threads and seen a lot of your posts on here and YB, great stuff. Your experience/discussions on the Procharger vs turbo setup steered me in the direction of twin turbos. I'm sure I will not be disappointed

 

Pleasantly surprised to see these sitting at the door this afternoon...
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thanks , I hope I saved you some money in the long run by steering you away from Procharger .

its sickening reading about the way Procharger treats their customers and the amount of money guys spend on repairs .

 

It's been a while since I have had a chance to get back...but have been busy making some progress. Got the cage finished and certified today. Also mounted the new MSD Grid ignition, parachute release, water to air cooler reservoir, fuel cell and battery box.
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Also got the engine back together, most of the fuel system plumbed, and turbos positioned.
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Getting real close !

Looks great .