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Next Gen HotRodder
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This be my first post here soooooo bear with me....

I have a 383 small block sitting in my k2500 right now. It is a tough little engine for what it is. Currently running stock TPI with around 400hp. However, as the title suggests, I've been looking into some boost... big boost. My goal is pretty substantial and broad, 600-800hp. And on a modest budget no less. I can get any part, its just a matter of time lol.

So here's the nitty gritty. As it sits the engine has a forged rotating assembly from Eagle. 4.03 over flat top pistons, 5.7" H beam rods, and the stroker crank. All of it forged. I know I'll need to get some dish pistons (probably) to get my compression down. Because right now, I think its around 11.8:1..... yeah. My heads are probably mostly to blame for that. They are some old twisted wedge heads from Trick Flow. Here comes a spec list for them...
combustion chamber: 64cc
intake volume: 180cc
CNC stainless 2.02i / 1.6e valves
1.25" single springs max RPM-6500
3/8top and 7/16 bottom studs
rough intake CFM at .5 lift is 229
rough exhaust CFM at .5 lift is 196
crane aluminum roller rockers
the valves are canted

Now those aren't the best heads around i'm sure, but I don't think they're trash either. Those specs are straight from Trick Flow tech support. I have a whole PDF on them. Anyway, I just don't know how these heads will breath with boost, keep them, trash them? Like upwards of 15-25lbs. So moving on to the other stuff, I have a high flow/pressure oil pump (it idles at around 40psi hot), the block is a 4 bolt 2 piece seal. So really, I'm all set on the short block I think. I plan to have it internally balanced with mallory metal. What I am curious about is cam selection, gasket types, blow through carb vs EFI throttle body.... that junk. My plan for the turbos is 2 60-65mm compressor wheels, fed by headers with at least 1 5/8 primary tubes. I think that will make my boost goals. ??? I know this is a big engine, not sure what the lag time will be like.

I know I'm going to need a high lift cam, but what about lobe separation and duration? I know that stuff can effect knock and timing. Especially in boosted engines. I just know nothing about it and how it effects it :( Summit has the cams sorted in little packs like 4x4, truck, street, dirt trakc, supercharged, exc..... Should I just pick a supercharged cam? i don't know :/ And as far as sealing this monster up, what are the best gaskets types for boost? I've just always used normal composite types and goo ARP fasteners. This will be my first boosted engine soooo.... yeah. My optimistic goal is like 800hp. But i realize that I may only get to like 600-700 (being a novice engine builder). I guess consider this a brain storm sorta thing. Not really sure how forums like this function. Any suggestions or criticisms are appreciated. What should I keep, what should I trash? lol
 

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Will this be race only with race gas? Even at that, 11.8 c.r. with that much boost is a disaster waiting to happen. You're much better off dropping the c.r. down to 8:1 or even less, 7.5 wouldn't be out of the question, allowing more boost. I'm sure someone here will tell you no sweat, 11.8 or 12:1 c.r. and big boost is done all the time...take any help like that with a grain of salt, even with turbos, even using all the tweeks, intercooled, timing master, water inj.

Also, 800 hp out of an older GM block isn't a healthy recipe, not by a long shot.
 

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Well first what type of boost? Roots blower, turbo, pro charger , screw blower what type of forced induction are u shooting for? Next what type of fuel will u run? and i wouldnt get caught up in boost numbers it takes more then boost to make good power.
 

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Well first what type of boost? Roots blower, turbo, pro charger , screw blower what type of forced induction are u shooting for? Next what type of fuel will u run? and i wouldnt get caught up in boost numbers it takes more then boost to make good power.
He said twin 60/65 mm turbos.

Oops, I see you caught that. :thumbup:
 

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Next Gen HotRodder
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Discussion Starter #6
He said twin 60/65 mm turbos.

Oops, I see you caught that. :thumbup:
lol Yeah, I tried to be specific about as much as I could. This engine is going to be primarily strip dedicated. I might drive it around on the street every once in a while, but that would be rare. As far as CR goes, I know my 11.8 is pretty atrocious for boost. I was thinking dish pistons, but I would need -28cc dish pistons to get my CR to just 8.5:1. :/ do they even MAKE dish pistons like that? I'm trying to avoid getting new heads, but everything about them seems to scream replace.
 

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Next Gen HotRodder
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Discussion Starter #7
Will this be race only with race gas? Even at that, 11.8 c.r. with that much boost is a disaster waiting to happen. You're much better off dropping the c.r. down to 8:1 or even less, 7.5 wouldn't be out of the question, allowing more boost. I'm sure someone here will tell you no sweat, 11.8 or 12:1 c.r. and big boost is done all the time...take any help like that with a grain of salt, even with turbos, even using all the tweeks, intercooled, timing master, water inj.

Also, 800 hp out of an older GM block isn't a healthy recipe, not by a long shot.
I never really did think about block integrity. Mine is a 4-bolt, but the caps aren't splayed. And I can't find a main bearing cradle for the life of me, not for a 350. Summit sells blocks ready to go if that would be better...? I know my HP numbers are ridiculous, but I'm kinda just going for maximum safe power at this point :/ My local engine shop says it would be safe.... but he's a bit slow.... I know my CR is to high. But to get mine low enough, the dish in the pistons needs to be too large. Which means new heads, that I'm looking at now. Starting to think already that I might as well scrap it all. -_-
 

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Is keep the pistons and the entire short block as it, and replace the heads instead. 200cc+ runners and 76cc chambers will help a lot. Combine that with a single properly built turbo and bigger injectors and you're done. No need for dual turbos no need to open up the short block, likely won't need more than 10-12psi of boost to hit 600hp either if you use a properly built turbo. One good single beats two half assed turbos every time.

Btw I'd plan on using e85 if it's available. Even if you need to test it before fill ups it's still much cheaper than race gas. It also allows you to drive this on the street if you so choose.
 

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Keep the rpm low and run a healthy stall and you should be okay around 700hp. High loads at low rpm and high rpm can both kill engines.
 

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Actually 2-bolt blocks are stronger in the webbing than GM 4-bolts. I went for billet splayed mains on my 383 blower motor, it's also a 2 piece main block from the '70's.

Being on a modest budget, build it for what you want it to do, going big boost isn't a build to skimp on.

If you go E-85 be aware it takes more than 1.5 times the volume over gas, so mileage won't be anything to brag about.
 

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1.3X the volume. That's important to get right when choosing injectors. You could try to hit it running pump premium but that requires lower compression and you better have the tune spot on.
 

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Next Gen HotRodder
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Discussion Starter #12
So far I'm thinking new heads. Maybe AFR 1120NP heads. 227cc intake runners and 75cc chamber. I can get my hands on a 2 bolt block from my brother most likely. Then it's machine work after that for the splayed caps and bore. haha this opened my narrow view quite quickly. I need to start thinking differently.
 

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Don't waste your time on putting splayed caps on a 2 bolt block. By the time you're done machining it all a SHP block is only a little more and gives you a much much better foundation. Use what you haveor buy some real equipment.

The 227 heads will require offset rockers, ideally a shaft system. Be sure to account for that. With boost 210cc heads could easily get you to your goal and use a standard valve train.
 

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X2 on the SHP block.
Depending on whose caps are installed and the angle of the out board bolt, you can easily wind up into the water jacket. By the time you get done prepping a factory block, you can easily have a grand invested in a 40 year old block that may have came in your Grandmas station wagon.

It sounds like you have a pretty good piece right now.
Sell it and help finance your new build.

A new set of heads with a bigger runner and larger combustion chamber will be a good thing as well.

Any kind of boost on gasoline leaves a very narrow tuning window.
E85 for sure. If this is strip only you may want to look into straight methanol.
On straight alcohol you can run a much higher CR.

sounds like a fun project.
 

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I have a set of Elemanators on my 388 and i used stud mount rockers and stud gurdles. Afr says they flow around 325 i belive. But they are pricey but i did use titanium retainers ect witch drove the price up.
 

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I was thinking dish pistons, but I would need -28cc dish pistons to get my CR to just 8.5:1. :/ do they even MAKE dish pistons like that?
They do http://www.summitracing.com/parts/jep-170817-8/overview/make/chevrolet.

I'll agree a new SHP block would be nice, but posts stating cost aren't accurate for even Anchorage, AK where I had my machine work done. Machining for the splayed caps was $200, I supplied the caps. If you do it yourself, yes, you could have problems. I'm only promoting caps because you used the words modest budget. Fact is, I did it, been there, done that. But nothing wrong with different opinions.

Ap, I'm surprised you'd recommend the more expensive option, seeing's you're doing a budget build with parts on hand, not all pricey parts...
 

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If you plan to buy an SHP block then buy the big bore,lol.You need new pistons anyways,,,build a 412. If you want a better crank then build a 434/440. use dual turbos 10 pounds, make over 800 hp pump gas.
If you buy a new 4 inch block and new 383 pistons I will laugh at you and you will feel silly.
you can use the 245 heads. custom 1 3/4 headers will work well.
cam around 230º/224º with rocker shafts and close to .600 lift

now you need a truck to harvest the power and drive line parts that can handle the power
 

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Ap, I'm surprised you'd recommend the more expensive option, seeing's you're doing a budget build with parts on hand, not all pricey parts...
I picked the cheaper heads and valvetrain... I just believe in picking and choosing where to spend your money. if he has a factory 4 bolt block going through the trouble of prepping a 2 bolt block just to gain splayed mains isn't worth it. And the cost to add mains is $200, what about the boring, honing, decking, etc that also has to be done to prep the block? If it were mine I'd run the factory 4 bolt block and be happy with less power, but if you have money to spend and want a sbc then an SHP block is a good investment.


If I had to do an SBC for this, I'd change heads to some cheap aluminum 200cc head with large chambers, run a single turbo, and get injectors. 3 major parts and be done with it.

A single GTX4294R would be more than sufficient for your goals.
 

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This be my first post here soooooo bear with me....

I have a 383 small block sitting in my k2500 right now. It is a tough little engine for what it is. Currently running stock TPI with around 400hp. However, as the title suggests, I've been looking into some boost... big boost. My goal is pretty substantial and broad, 600-800hp. And on a modest budget no less. I can get any part, its just a matter of time lol.

So here's the nitty gritty. As it sits the engine has a forged rotating assembly from Eagle. 4.03 over flat top pistons, 5.7" H beam rods, and the stroker crank. All of it forged. I know I'll need to get some dish pistons (probably) to get my compression down. Because right now, I think its around 11.8:1..... yeah. My heads are probably mostly to blame for that. They are some old twisted wedge heads from Trick Flow. Here comes a spec list for them...
combustion chamber: 64cc
intake volume: 180cc
CNC stainless 2.02i / 1.6e valves
1.25" single springs max RPM-6500
3/8top and 7/16 bottom studs
rough intake CFM at .5 lift is 229
rough exhaust CFM at .5 lift is 196
crane aluminum roller rockers
the valves are canted

Now those aren't the best heads around i'm sure, but I don't think they're trash either. Those specs are straight from Trick Flow tech support. I have a whole PDF on them. Anyway, I just don't know how these heads will breath with boost, keep them, trash them? Like upwards of 15-25lbs. So moving on to the other stuff, I have a high flow/pressure oil pump (it idles at around 40psi hot), the block is a 4 bolt 2 piece seal. So really, I'm all set on the short block I think. I plan to have it internally balanced with mallory metal. What I am curious about is cam selection, gasket types, blow through carb vs EFI throttle body.... that junk. My plan for the turbos is 2 60-65mm compressor wheels, fed by headers with at least 1 5/8 primary tubes. I think that will make my boost goals. ??? I know this is a big engine, not sure what the lag time will be like.

I know I'm going to need a high lift cam, but what about lobe separation and duration? I know that stuff can effect knock and timing. Especially in boosted engines. I just know nothing about it and how it effects it :( Summit has the cams sorted in little packs like 4x4, truck, street, dirt trakc, supercharged, exc..... Should I just pick a supercharged cam? i don't know :/ And as far as sealing this monster up, what are the best gaskets types for boost? I've just always used normal composite types and goo ARP fasteners. This will be my first boosted engine soooo.... yeah. My optimistic goal is like 800hp. But i realize that I may only get to like 600-700 (being a novice engine builder). I guess consider this a brain storm sorta thing. Not really sure how forums like this function. Any suggestions or criticisms are appreciated. What should I keep, what should I trash? lol
Since you are using a TPI induction, you can look to cars/companies that have turboed such a setup.
Main comapny that comes to mind is Callaway. From 1987 to 1991 Chevrolet offered a twin-turbo system as an option. If you checked the RPO(Regular Production Option) B2K box when ordering your 1987-91 TPI 350 Corvette, you car was sent from Bowling Green Kentucky to Callaway at Old Lyme Conneticut.
1987 B2K's were rated at 345hp/465lb/ft torque and had a top speed of 178mph and cost $50,000.
1988 there were 105 B2K TTVettes ordered with a total of 125 tt Vettes being built. 382hp and 562lb/ft torque was available.
1989 saw 51 B2K's ordered with 68 twin turbo Vettes total being built by Callaway.
1990 Output was 390hp/582lb/ft torque with only 58 B2K's being built. The 1990 ZR-1 Corvette with its 375hp/385lb/ft, DOHC, 7200rpm, all aluminum Lotus designed, Mercruiser built LT5 was released.
1991 Ticking the B2K box got you 403hp/582lb/ft of torque. 62 B2K's were built this year. 1991 was the last year that Chev. was offering the L98 TPI engine which is the basis for the TT B2K car.
In total 497 (B2K) Callaway Twin Turbo Corvettes were ordered through the normal sales channels. However, before the Callaway Twin Turbo option went away, Callaway and Deutschman went to work to provide yet a more powerful and stunning car, the Callaway Speedster. A small amount of the final twin turbo cars and the Speedsters (10 Series 1 Speedsters w/ L98 Twin Turbo) were designated 500 Series Callaway Twin Turbo Corvettes. These unique cars came with OZ racing wheels and Bridgestone Potenza tires, a "500 Series" dash plaque, "500 Series" intercooler badge, special car bra, car cover and floor mats. (wiki)
Regarding the "production" of the Callaway Sledgehammer, Reeves Callaway used a production Callaway Twin Turbo Corvette, 1988-051, to be precise. The car was, in fact, a production car, with all options found in other Corvettes the same model-year(wiki)

All of these Twin Turbo B2K Callaway cars got Chevrolet 12 month, 12,000mile warranty.(tires not included lol)


Underhood pics of the B2K twin turbo Corvette.



Rams horn which brings air from both intercoolers into teh t-body




Top view


Emmissions tag on side of intercooler


The first 4 of these 1987 engines and one other, were truck blocks. Then the proper blocks were used.

Here is the list of mods directly from a gentleman who actually did the work at Callaway.
Disassemble and acid dip engine
Block
magnaflux
remove any casting flash that was thin and might fall off
remove cam bearings and oil gallery plugs
check decks
install billet 4 bolt main caps with splayed outer bolts on center 3 positions
line bore
line hone
bore block +0.005 with stress plates in Sunnen CK10
pressure wash bock
hand wash with soap and water
install Speed pro cam bearing and hand fit
install new oil gallery plugs

Heads
disassemble and degrease
visually inspect for casting flaws
check and correct guide clearances as needed
3 angle valve job
lightly surface the head to insure flatness
assemble with Speed Pro intake valves and valve springs keepers and valve seals.
I think 130 lbs on the seat and forget what they were open spring height was checked on every valve and spring.

Rotating assembly
Early crankshafts were Scat and later changed to Callies I think after the the first 25 or 50 all forged steel
Pistons forged Cosworth with Cosworth pins dished with pressed pins and guessing around 8.5 /1 compression but that is from memory only
Speed pro plasma moly rings file fit to each bore
All cranks and rods were magnafluxed
Connecting rods new rod bolts and big and small end bore honed for correct fit
Rotating assembly balanced to .2 gram flywheel damper and clutch each balanced separately to .2 gram
pistons and rods were hand sorted into sets initially to minimize metal removal and within .1 grams as the scale we used could easily read that
Cleveite delta wall bearings hand fitted to each journal using selective fit shells
All engines assembled by a team of 3 people and resopnsible for their engine on a signed build sheet that is unfortunately long gone now as they were for in house use should there be a warrentee claim of any kind. It has been 20+ years and forget how and where they were numbered or initialed but if you see some non GM stampings on your B2K engine we probably put them there. My guess we used our production number.

Miscellaneous
Intake plenums were machined for a Calloway logo on each side
Plenums intake runners throttle body top cover and valve covers were painted with black wrinkle finish and baked under heat lamps.
Timing chains and gears were new HD parts and remember Cloyes though could have been branded through Speed Pro at the time.
Gaskets were Fel-Pro though pan and valve cover gaskets were reused GM parts
Oil pumps escape me right now if I happen to think of it will add to this post.
All engines were pressure tested the coolant system with compressed air with soapy water sprayed on by hand and I can not imagine that we would have not pressurized the oiling system to check for oil to lifters rockers etc. but that is a hunch based on our standard shop practices.


And here is a 1988+ Callaway B2K spec sheet.


The king of all Callaway twin turbo OCrvettes was the SLEDGEHAMMER. It is a C4 Corvette which uses a highly modified 350 cubic inch engine, 2 turbos, 2 intercoolers to make 880hp. It along with the Callaway Aerobody kit allowed the Sledgehammer to attain 254.76mph.

Sledgehammer with Callaway Aerobody kit(available for conventional C4 Vettes, and for the 3" wider rearends of the 1990-1995 ZR-1 LT5 powered C4 Corvette)


Back end of Sledgehammer. Notoce the 4 Supertrap adjustable mufflers


Magnesium 16x8" to 17 x9.5" depending on year,there were 17x11" and a later 17x13" size made for the ZR-1 Corvettes. All of these MAgnesium rims were made by Dymag of England. Some of these rims are worth more than the cars that wear them(B2K models usually excluded unless the car is thrashed)



Video of the LSedgehammer speed record breaking attempt, driven of course by the late legend, John Lingenfelter.(also known for his twin turbo Corvettes). After setting teh record at the Transportation Center in Ohio in November of 1988, Sledgehammer was driven back to Old Lyme in Conneticu thereby demonstrating the advantages of turbocharging and fuel injection.
Doing laps, even in the rain, good test of the windshield wipers.

General Information
Price: $400,000
Miles Per Gallon: 10/19 mpg
Curb Weight: 3671 lbs
Layout: Front-Engine/RWD
Transmission: 6-Speed Manual
Front tires: 275/40/17
Rear tires: 275/40/17
Engine
Type: Twin-Turbo V8
Displacement: 5733 cc
Horsepower: 898 bhp @ 6250 rpm
Torque: 772 lb-ft @ 5250rpm
Redline: ---- rpm

Performance
0-60 mph: 3.9 sec
0-100 mph: 9.4 sec
Quarter Mile: 10.6 sec @ 127 mph
Skidpad: .98g
Top Speed: 254.76 mph
Braking, 60-0 mph: 122 ft
Slalom Speed: 65.6 mph


Making 898hp from 350 cubic inches, is moreso easily accomplished today, than it was 25 years ago in 1988. The more impressive part is the packaging of that 350 cubic inch engine, and all the ducting that is needed to feed air to the turbo and from the turbos along with being cooled and introduced into the engine. Then factor in the turbos themselves and the heat shielding that was needed to prevent cooking the interior, along with the oil coolers, air charge coolers, powersteering coolers, brake cooling, trans cooling, differential cooling. In 1991 Callaway began using "The Wonderbar". This is a modification to the air intake system in which the front frame is modified and actually used as a duct to route air to the turbo's. This modification provided greater air flow to the turbo's which resulted in an increase in power. The thermodynamics involved in building this car is amazing. In 1988, it blazed up to 255mph, then hit the highway for a 550mile at 70mph cruise to its home diggs in CT.
Making power, and making it last can prove difficult. Hopefully you find some of this info helpful.

peace
Hog
 
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