Advice needed - Possible 383 LT1 build

[Greg]

I'm working on building a new short block for my M6 97' Z28 and started kicking around the idea of stepping up to a stroker. My initial plans were to re-use a stock crank and add forged rods, pistons, ARP everything, etc. My engine builder suggested going fully forged and then I brought up stroking it. My goal for the build is to be a reliable street/strip cruiser and keep it somewhat budget. I don't want to replace too many parts I already own so I was wondering what you think my limitations are. I would be happy with around 450hp/450tq (at the engine) and don't think I would be too far off. Besides putting $1k in port work in the heads where do you think i'm leaving extra hp on the table? Should I use a bigger cam? I don't want to spin it much over 6,600 rpms becuase of the Opti. Would the heads benefit from bigger valves without additional portwork? Get the intake ported?


Heads

• Re-machined stock valves
• Patriot Performance Gold Dual Spring Kit, .650"
• ARP Cylinder Head Bolts (12-Point)
• Trick Flow Pushrod Guideplates
• ARP Rocker Arm Stud Kit (7/16")
• COMP CAMS PRO MAGNUM ROCKER ARMS SBC 1.6 (7/16")
• GM Performance Hydraulic Roller Lifters
• Milled 20 thousandths
• Gasket matched

Intake/Exhaust

• LPE Cold Air Intake
• Trick Flow LT1 Air Inlet Elbow
• 52MM TB
• Long Tube Headers - Emissions deleted / EGR Block off plates
• 3" ORY
• Hooker Cat Back w/ 3" Cutout

Camshaft

• Advanced Induction 226 / 234 - .567" / .567" - 110 LSA
• "Easily our most popular daily drivable grind for 350cid applications. Typically makes peak power at 6300-6500rpm on 350-355cid short blocks.
  Properly tuned it will run and drive well in M6 cars w/ stock gearing. A4 cars should run a 3.42+ rear end gear & 2400 rpm converter minimum.
  Can pass emissions in some states."

Misc

• March Performance Pulleys
• LT4 KM
• MSD Coil
• MSD 8.5mm Super Conductor Spark Plug Wires
• 30lb modified Bosch 3 fuel injector set

[birdie2000]

Do you plan to spray it? For your relatively modest goal of 450 hp/tq at the crank, if you're not going to spray it I think you'd be better off putting your money into the heads instead of forging and stroking it. A heads/cam setup from AI on a stock shortblock with that cam can easily make those numbers.

[nascarnate326]

Id go 24x before I went stroker.

[Fox Slaughter]

Didn't finish reading but will edit as I read more.

Heads/Cam stock bottom end will make that.
Most guys are laying down 350rwhp figure 15% drivetrain loss so roughly 400bhp.
Joel laid down 373rwhp with that cam.

"Recommended Usage: Stock 350 cid - 383 cid short blocks with piston relief/dish volumes of 5-16 cc. With supporting modifications, manual stock short block F and Y bodies will typically produce 395 - 435 rwhp SAE corrected or 415 - 455 rwhp STD corrected depending on cam and valve train selection. Purpose built 355-396's typically manage anywhere from 440 - 500rwhp SAE when utilizing our manifold work & valve train. *Please note this head work requires your castings! Click here for packing and shipping information of your castings."

415rwhp is roughly 477bhp.

[birdie2000]

350rwhp assuming 15% drivetrain loss would be around 410bhp. (350/.85= 411.77) and 415rwhp would be about 488bhp. Joel's car with that cam is making 438bhp assuming 15% loss. Major props to Joel because his car makes great power, but those numbers are probably optimistic for most average builds. Getting even their basic 190cc heads/cam package would be pretty much guaranteed to meet or exceed your goals. Their packages tend to have an excellent torque curve too, further diminishing the need for a stroker for your goals.

I second the 24x thing. I did it and love it. It's nice not worrying about the opti, and it makes finding a capable tuner so much easier.

[JoeliusZ28]

Greg I know we discussed this a bit on facebook, I think this is some good advice here. In my opinion strokers were a popular choice for the LT1 strictly because of the RPM limit the opti sticks you with. I think I would also go 24x first and give the 350 the RPM it wants, especially since you'll have the 4-bolt main to take it. The other option is both! Even with some more stroke, a 383 can still rev pretty good!

I still like the idea of using a stock crank and forged everything else. Stock cranks are strong, no need to reinvent the wheel and waste money IMO.

Edit: also make sure you get the bottom end balanced... that goes a long way in keeping things in one piece.

[Fox Slaughter]

The stock crank is generally given a 500bhp recommendation.
Do not get an aftermarket cast crank. It will most certainly break.

[FASHOOTER]

Forged 383 AI Heads and cam......DO IT!