This is what I'm getting ready to install:

382 LT1
LT1 block, std. bore, splayed mains, stroker clearanced
3.8" stroke 4340 crank, Scat 4340 I beam rods, std. hyperutectic pistons (yes that's right)
internally balanced for LT1 damper
LT4 ED timing chain
Melling LT1 oil pump with white spring and welded pickup
GM847 cam
1.6 promag rocker arms, NSA 7/16 stud, comp R's and #977 springs
LE LT1 heads, 275/200 cfm
30# SVO injectors
58mm TPI throttle body with adapter to use on LT1 (TPS adjustability)
Pacesetter coated longtubes with y-pipe
LT4 KM
CAI, 1LE elbow, descreened MAF, crane HI-6R, pulleys, and borla catback

Figuring 415 RWHP and somewhere around 440 RWTQ. I'm considering spending next years tax refund on an upgrade to a set of Lloyd's AFR LT4 210's with a matching intake and 36# injectors...wondering if the increase in flow would be noticeable and worth the cash? Looking to hear from those who have run these heads. With the 383 I'm thinking the 847 will be plenty streetable with acceptable mileage and I just want to make the powerband perkier without loosing midrange TQ. This is a street/track car.

If not I'll probably spend the $$$ on a 12 bolt and a better driveshaft

 

If you are running stock brg clearances you don't need the white spring.
I would pick another cam.
The heads will give you 75-100FWHP over stock unported. I would go with the 227's and no they don't need special rockers.
Use the stock lifters if they are not worn out if they are get stock replacements.They will take you to 600-650FWHP@7000RPM's with the right springs. Get 42#@45PSI injectors if you are serious about HP and a 1300CFM AS&M mono blade. 1-7/8 headers about 30-32" long with 3-1/2"collector
Put your compression at 12-1/2 to 1 and with a larger cam say 250-260@50-112+4 with .680 lift(talk to your cam grinder) and you will be safe with a 8.9-9.0 DCR on pump gas.

Now this is all assuming you are serious about HP. This should get you 625-675FWHP and thats a bunch for a street machine. 5-530 to the tire depending on trans and driveline and you gonna need a rear end too.

 

I just want the white spring just to help out oil pressure at higher RPM's, dont necessarily need it. Would rather have a little too much oil pressure instead of not enough, but yeah, all my bearing clearances are std.

If I stray from the GM847 I'll probably get a custom...but I'm tempted to not do that because I might change heads later. 250/260 seems kinda big considering I still need to drive this thing daily for the next year, of course I can always change it later, too. Cam swap is no big deal. May go to a custom grind with the heads and intake.

Gotta use the Comp R's with the 977 springs...the stockers are too soft and will collapse with the pressure of that spring. I think the 987 spring is about as stiff as I can go on stock lifters, but right now I'm running Comp high energy lifters anyway.

Built my 10 bolt but I'm still on borrowed time

 

that sounds like a beast!!! Im trying to achieve about 440 to 450whp. Think its doable with my setup in the sig?

 

I think it's possible, but it wouldn't hurt to step up tp a bigger throttle body...

 

sorry to hi-jack the thread, but I had a 58mm BBK, and throttle response was horrible. I think I noticed the most out of my setup, when I swapped the 58mmtb for the 52mm...

 

The only thing I wounder about is the "58mm TPI throttle body with adapter to use on LT1 (TPS adjustability)" why not just go with a LT1 TB and oblong the holes on the stock TPS, its free and works fine. If the heads will flow well enough to suport it you should be close to what you are looking for. I made that HP with a CC306 but less TQ then you want through a good flowing set of AFR 195's on a stingy dyno.

 

More compression,bigger TB,and a larger cam will do it.

 

like which throttle body?

 

I had that TB when I was originally planning on building a TPI motor. Then I looked into it and realized that the motor would never reach it's potential using MAF TPI gear, so I chose to build an LT1 instead. Couldn't ever sell the TB so I got creative. The adapter took like 2 minutes to make using GM connectors, and with the TPI TB, the TPS slots are cut in a way that not only allow you to adjust idle voltage, but WOT voltage as well.

I had it on my LT1 once and it worked fine...but took it off because the car was going to sit for a year while I was in Korea. Never got around to putting it back on because I didn't think I needed it yet. I'm boring and need a life

 

dont know if your confused, but my car is a lt1! not a TPI

 

lol, no, I was referring to the throttle body on my car and what I did for tunability, not which one you should get for yours. If you dont like the BBK units, you could get an AS&M LT1 TB, I've heard they're nice pieces...kinda steep in price though. Most people seem to like them however. Holley seems to be another decent choice. The BBK seems to carry the average brand of throttle body.