Hi,

Getting on with my set-up, but as I bought the motor used, Im unsure of the power output. It would be useful to have a rough idea. Heres what done so far:

406ci SBC

Dart LIttle M block 4.155" bore,
4 bolt splayed with ARP studs
callies dragon slayer crank with 350 mains
Oliver billet 6.00" rods
JE dished blower\nitrous pistons 8.5:1 comp. ratio
lunati solid roller camshaft .601 I. .606 E.
AFR 210 cc heads 73cc's 100% cnc ported race head
titanium retainer and 10 degree locks
k-motion springs
manley inconel valves 2.08 1.60
lunati lifters
comp cams pushrods
scorpion 1.5 roller rockers
VTO stud girdles


Blower is a Procharger D1SC, with a 4.25" pulley.


Fuel pump is an Aeromotive Eliminator, probably going to use -10 an lines

Carb is a Holley 700cfm, modified for blowthrough

Any help would be great.

 

What size duration on the cam?

Most power I've seen from any D1sc setup was 800whp which alot of people found hard to believe, they just dont think it can put out that much air flow. It may have been severely overspun.
Your setup should get near that with enough boost. I do not know what a 4.25" pulley will put out boost wise, but 12-14psi on that thing should get around 700whp if your turning near 6K rpm peaks.

My 401 with AFR 195's made 640 on a mustang dyno thru a big stall converter on 12psi. For reference, a local cobra stang made 747whp thru a manual trans, and when switching to TH400 with larger stall speed, it made 637whp I think it was, and I believe that was on a dynojet which reads lower than Mustangs.

You have more head and cam than I did, even tho mine was turbo, I dont think the power would be too far off. Depends on how much the converter eats up and that 9" rear end. I ran thru stock 10 bolt which doesnt consume power.

Dont put too much into the dyno numbers, just worry about what it runs at the track

 

Thanks for the reply. The duration is 258/264, lsa 115. Its as much as anything to get an idea for the the converter, which I havent yet obtained. I may be limited by the carb, as I recall its 1cfm per hp on a blowthrough, ma be wrong on that though.

Also what rearend gears would be good? The car is gonna be used 90% on the street, so the 4:11 ones I have, are probably a bit wild

 

With big power cars, you dont need alot of gear to go fast. With 3 speed auto with no converter its nice to have highway type gears. I love my 2.73's but with my new setup I'll likely go to a 3.23 rear end, or maybe a 3.42 with a 28" tire. I'm not sure yet.

Generally gear to match its 1/4 mile performance, rpms and mph. 140mph in the 1/4 is about what a 700whp car will do, maybe even more if you are around 3500 lbs raceweight. Given that, and assuming near 6400-6500 rpm peak power with that cam (just a guess, it should be near that), with a standard 26" tall tire you would want to run 3.42's but for more street use, I'd like to see 3.08's. Keeps cruise rpms down alot more

 

Throw the carb in the garbage. Forget about using a carb in blowthru application with forced induction ,nothing but problems. EFI is the way to go
with forced induction you`ll save yourself a headache and broken parts.

Dont be too hasty to change your gear yet until you try it out on the street.
Put it to you this way if i put 2.73 gears in grandma`s car she would complain how much of a pig the car is.IMO street gears should be in the 3.5+ range anything below that makes the car a dog.

 

700cfm carb maybe a lil small but it will work just fine.and dont listen to daverr everytime somone says there going to do blow threw carb he gives the same reply.
blow threw carbs work just fine, just make sure u get a carb from a reputable place if ur not modifying it urself

with a non od trans i wouldnt go over 3:42's or 3:73's if u have a 28inch tall or taller tire on the car. but honestly gearing will depend on how much power it does make. the more power it makes the less gear ur going to need,

 

nothing beats the bog ,stumble and flooding of a blowthru carb. I guess some ppl find venturi precise enough.

 

I never had a blow thru but i like what EFI does for me. But my car CERTAINLY isnt a dog with 2.73's It works for the rpm range I achieve. Its hard to make a dog out of any 800hp setup

 

I did originally have most of the EFI stuff for the car, but I needed some cash to do some other bits on the car. So I sold it all off, and went for the carb. I would have liked a 750CFM, but this one came up cheap. It was built by an administrator over at Turbomustangs.com, who runs a very similar one himself. I think he knows what hes doing

 

put 3.5+ rear gears in it ,then you will be certain. No its not hard to make a dog of any 800hp setup when your chassis/drivetrain is off.

2.73 works on stock motors , your just handicapping yourself with those gears. How many 800hp cars out there use 2.73??? I know of no cars in my area running that kind of gear , not even a 1000hp pump gas 615" bbc on motor street car.

 

turbo cars do not like gears period, if he put 3.42 or higher gears in his car he would run out of gear long before the end of the 1/4

my turbo v6 car picked up a half a second with a gear change going from 4:10's to 3:23's. 4 :10's = hardly and boost in first gear.car even 60 fts better witht he 3:23's.
turbo cars are entirely depended on load

supercharged and nitrous cars will go fast with the higher gears

 

u wont have any issues with that carb he has carbs on everthing form 6/7 sec drag cars to turbocharged daily drivers

 

Turbos dont care about what gearing you use.

My 87 GN twin turbo v6 has 3.73 gears and has no problems spooling the turbo in first gear. On the street i have ran it up to 20psi of boost in first gear ,way to much for the street but it did no problem. Your turbo/chassis/drivetrain is off ,if it hardly boost in first gear.

 

It would accelerate faster if it hooks, but do the math. You match gearing to rpms and mph in the 1/4 mile.

My motor peaked around 5500. So at 140mph traps, 2.73 gear, 26" tire thats 4941 rpm but with converter slip, I trap near 5200-5300 or so. No bad, but I COULD gain some by going with abit more gear, but even a 3.08 next size up will be near 5800 rpm with converter slip, and thats all i'd beable to do on this motor. May run it to over 6K but thats a waste, power was already dropping off.

Now my new motor will go to near 7K rpm so I can get away with 3.42-3.55's, and JUST maybe slightly over rev with 3.73's at 140 mph. BUT my new motor will likely get closer to 150-155 mph which now makes it best to go with a 3.23 gear.

Now that I do alot of street cruising with a Th400 trans, I will buy a rear with 3.08's more than likely.


If I went with a 28" tall tire, the gear size jumps up again. For my 140mph traps, 3.23 would likely be best with a 28" tire and 5500 rpms peak hp

All motor cars rev alot higher too than most boosted cars so they need more gear. I would have run 4.11's in my 383 all motor car for best times...but once I started spraying it, the 3.42's worked well enough and 3.73's might have been optimal.

 

then go on the turbo forums and tell everyone who puts in a numerically lower gear and goes faster that there doing it wrong

 

Im talking about the turbos by themselves. Your argument, saying turbos need low gearing or they wont work is false. This argument is based on a misconception that gearing creates load that is needed to spool the turbo.