Been reading and looking and decided to run a single turbo set up in place of my naturally aspirated 383. First off need to drop the compression from around 12.5 to 9.5 by changing out the heads and wanted to run the patriots due to seem to be a good bang for the buck but I need a 76cc chamber to get the compression I need with a flat top in my 383. So looks like either procomp 190s or afr 195s. Limited to those because of the small runners on the older hsr I have. Able to get a master power t70 turbo with a 96mm exhaust from a buddy who just upgraded his mustang to a larger turbo for 300 bucks and it has less than 5000 miles on it. Thought it was a good deal. It made 600rwhp on his stock bottom end 302 prior to splitting the block. His cam was close to what I run and afr 165 heads and ran it at 12 lbs of boost. So on a 383 I would hope to get a little more. Well the problem is you can get a single turbo set up for a mustang down at walmart (well almost) and cant find anything for a 3rd gen f-body. (I have a 92 formula) I have been considering building them myself but dont want to if I can buy a set. I really dont want to spend the next couple weekends having to build a set. I have heard someone say that you can run a lt1 vette manifold upside down and build off that???? Would go quicker to build off of. Looked into getting a set of those cheap twin turbo ones and using them as a base line and change up the ends and go from there. I wish you could just get a kit like you can get for mustangs but I guess we didnt show enough interest in turbos to have companies offer them for us. So what do I do now? My buddy is now making 750 rwhp with his 92 gt and stomping on most of anything on the street here and I would like to join in on the fun. He keeps it in the 650 trim most of the time and if I can get him there I would be happy.My car is a little lighter than his gt so could get away with less hp than the 650 really.He got the 750 on race gas and the boost at 15lbs but says he can run up to 20 with the setup. He built a dart block and has a couple grand in the short block to make it live at 1000rwhp with the afr 185s on it I am sure he can get there if he pushes it. He also does it with a blow through carb set up too. Keeps saying scrap the efi but I enjoy getting 20 mpg and having great driveablilty with a car that now can run 11.7 @ 118. Any way really need some direction on what to do with the the headers and mounting of the turbo on this thing. By the way I have to keep the A/C as I live in FL and this is my daily driver. I already have a 9 sec 94 z28 for the track and this is to be my fun car I can take out and go anywhere. Any help would be great. Also if anyone has recommendations on heads with 76cc chambers or has a set to sell I am listening and why I made mention of having to change them. Thanks to all that respond and I will keep combing the archives of threads.

 

what are the specs of your flattops? at 5cc valve reliefs i come up with a 11.9 to 1 compression with 58cc heads? 12.5 seems really high

Even with AFR 75cc chambered heads, that only drops to 9.8 from the 11.9 i calculated. abit high for boost but if its low boost and a good tune it should work ok

Call AFR tho, and they will set you up with whatever combustion chamber you want, maybe even get a 80cc

BUT i dont think your current shortblock will like boost. Might be a good idea of upgrading pistons/rods to something more suitable for your application, especially if your plan on 600rwhp or so. Stock Lt1 runs are only good to 500hp from what i've seen. maybe able to push 500whp with a good tune and low rpms but thats pushing it man.

But a single turbo at 12psi on a 383 will make around 600whp with good heads and that HSR intake

actually i've heard L98 vette manifolds that you can run upside down and run turbos on top of them For a single setup you may beable to cut the flanges off a good set of shorty headers and flip/turn them around to face towards the front of the car and then run piping to a single turbo flange.

 

rods are actually powder metal aftermarket bushed for full floaters and shot peaned. I worked with a guy that built roundy round motors and used them in 383 cheater motors that turned 7500 rpm and ran alcohol. So I would guess they were around 500 hp. I plan on turning 6000 at the most. I have seen stock lt1 bottom ends hold 575 rwhp with a procharger set up on a buddies car and my own lt4 bottom ended 96 formula makes 420 on the motor and I have a 150 wet shot on it but never dynoed it on the spray. Guess it would be a touch over 550 and I turn it 7000 rpms on occasion. So even if they were the lt1 pieces I think they would be ok at 6000 and 600rwhp. I have the probe moleculites and I think the valve reliefs are 6ccs. The pistons are 15 in the hole and I can run up to a .060 mls head gasket. Heads on the car now are cut .030 thousands and I have .030 compressed gaskets to get the 12.1 that I came up with. So with the .060 76cc 15 in the hole on a compression cal. it shows 9.5to1. I have my own tuning stuff and a wideband set up so getting it tuned will be possible and I would rather run a little higher compression and have it more responsive out of boost and run less boost and timing to make up for it and still get the same peal Hp as a low comp and high boost. I have been watching a few buddies build their turbo stuff and a few went back in and changed over from a 8.5to1 set up in favor of a 9.5to1 to get it to run better out of boost. Makes sense I guess. Can always run race gas if needed to go up on boost for special occasions like track time or needing to edge out someone on a close race in low boost trim. My buddy with the mustang also build his big motor on 9.8to1 over the 8.5 he had with the stock bottom end set up and he had the same reasoning that he wanted better response and it to run better out of boost. More efficient engine. Also have a steel crank and plazma molly rings on the probe pistons all stuffed in a 4 bolt main high nickel truck block. So the short block should be good for 500 to 600 hp.I saw bbs is offering a header set up again but only pass side??? what do you do for the driver side stuff and the crossover? Been digging around and all I have found so far for premade headers. If anyone has a set up I am up for ideas on injector size and if you went to a 3 bar map and cyclone ecm.

 

i'll let others chime in on headers/manifolds since they know more than me, but searching around could show some setups and you can get ideas there

I would think tho that running a thick gasket with large chambers would yeild a poor quench height and i'm not sure you would want to do that with a boosted motor looking for high hp

 

What is the difference in running a dish or larger chamber? I can get the afrs ordered with 80ccs if needed. Space is space just up or down. Look at a big block that have 116cc heads or larger. Only looking to run around 10 lbs on pump gas. My buddies 302 made 550 on 10 lbs with that master power and if my 383 cant do a little better its a sad day for chevy.

 

it wouldnt be a problem as long as you keep quench height to a proper spec.

quench hieght from the piston at TDC to the head deck should between .035-.045". this includes how far the pistons are in the hole below engine deck plus the gasket thickness

So adding a thick gasket kinda throws this distance off.

I'm not sure why it is, but i've always heard its best to run the proper piston specs to get the target compression rather than run larger head chambers to get the compression down. But search around for information concerning that and see what others say. I dont run a turbo motor or anything like that so i'm not sure if thats such a bad idea or not. I just know quench height is something you want to achieve for best combustion and to be less detonation prone

 

well figured it out to the t. With a 385 .040 over on the bore and a 76cc head -10 in the hole a .042 compressed mls gasket flat top piston with -4cc reliefs will put me right around 9.5 compression. I think it is at 10 in might be more but sure it isnt less making compresson possibly as low as 9.2. So I will be fine running at standard type gasket with the standard 76cc afr 195 head. So those problems are now gone knowing my friends car is at 9.5 and he runs 12 on pump gas with is carb blow through set up. Now need for some of the other turbo guys to chime in on what to run for a header set up with a master power t70 turbo and a/c.

 

im looking to for somthing hope some one can give pics or somthing
thanks guys

 

click here for turbo header needs http://www.bermudezcustomdesigns.com/

 

did i read that wrong. for a single turbo sbc shows comes with one passenger side hedder? whats that about.

 

nope you dident $$$$

 

thats a crock of **** for mild steel and only one hedder with no crossover.
ive got 550 bucks in my stainless steel turbo hedders a right and left and a crossover. and 5" mild steel exh and v band flages to connect the crossover to the hedders

 

well then, start your own business, become a sponsor and advertise.

 

Here's my single turbo exhaust using the c4 manifolds and 2-1/2" J-bends. Most of you have probably already seen these. The fabrication was actually pretty easy, cheap, and only took a couple days using a spare pair of heads to cut and weld the manifolds how I wanted.

 

na ill stick to just building my own stuff. i dont have enough time to advertise and build.