Help select turbo specs for 249 CI Stroker

[tonysmach]

Engine is getting close to done and I need to select turbo. Build is as follows:

Forged internals, H-beam rods, forged pistons 3.820, 3.625 steel crank
218/218 DLS cam
GN1 aluminum heads (upgraded valve springs) port matched to Champion stock ported intake
80lb hi z injectors
Single Nozzle Alkycontrol
Dusty Bradford PTC 9.5 N/L spec'd for 6765 billet turbo
70M Kenne Bell Plenum and TB

Mostly street driven but will see plenty of track time. My questions are:
Do I go with ported S or H cover?
Do I go with .63 or .85 exhaust housing?

 

[TurboTnZ06]

I have a stroker, GN1's, 210/210 roller, 70mm, 80# inj, etc, etc, but with a 3000 stall 9/11 L/U and a little E cover 3/2 66mm TE45a .63. It's a beast on the street with a small turbo and low stall converter it still spools almost as fast as a stock turbo on a D5 stock 13.0 sec TR. On my stroker, anything over 7#'s boost I have traction issues on the street as it hits hard off the line. And that's just pump gas. I'm installing dual alky (just got some wiring left to do) to turn it up.

I'd say .63 exhaust and a 6765 would be a nice choice if the converter is spec'd already for it. I don't know of the advantages of the S or H if its a street car mostly.

 

[bison]

I'd run the 6765 with a .63 ex and whatever cover you are currently or last ran. There isnt crap for power in the cover. Save the $ you would spend on more turbo and buy an AMS 500 for some better boost control on the street. I'm assuming you are looking for 650-700whp if not I'd go smaller on the turbo

 

[tonysmach]

Thanks for the replies. I am stepping up from a TE44, and stock cammed engine. Yes, I am looking for 650+whp. AMS 500 and FAST XFI is in the future plans before next spring. I am looking for quick spool on street with the 6765 DBB. Is there that much difference in spool up between a .63 and .85 with a GN1 headed stroker? Compression is 9.0 : 1.

 

[tonysmach]

Is it correct to say that a .85 housing is not going to be an advantage until boost exceeds about 25 psi on 6765?

 

[bison]

Is it correct to say that a .85 housing is not going to be an advantage until boost exceeds about 25 psi on 6765?

Id say there is little advantage till you are over 650whp. The Precision .63 is alot closer to the Precision .85 in flow than the t-netics .63 is to the t-netics .82 or the Garrett .63 is to the Garrett .82. When in doubt go with the smaller housing if looking for a quick spoolup from a roll. You will need some good valve springs and gear the car to trap 137-138mph@5900 with 5% slip. It will run the number.

 

[tonysmach]

Id say there is little advantage till you are over 650whp. The Precision .63 is alot closer to the Precision .85 in flow than the t-netics .63 is to the t-netics .82 or the Garrett .63 is to the Garrett .82. When in doubt go with the smaller housing if looking for a quick spoolup from a roll. You will need some good valve springs and gear the car to trap 137-138mph@5900 with 5% slip. It will run the number.

Thanks Brian, that is good info. Looks like the .63 housing is the one for me.