[Landshark928]

Anychance someone can run the numbers for me if you have time and are bored.

Killed my 434SBC and I'm replacing it with a 421". Hoping the shorter stroke likes the high rpms better. Feel free to let me know if there is anything I can improve for easy HP or to make it safer. Looking at 150-200 shot of nitrous very occassionally, mostly NA use at higher rpm Road Race and Drifting. Shifted around 7200rpms with the 434". Short block is already assembled.

Dart Little M Block 4.155" bore
Callies Dragon Slayer 3.875 " Stroke
Howards 6" H-beams
Probe forged pistons 17cc dish.
Pistons are 0.003" out of deck.
Felpro 1004 Gasket for .038" Quench
220 Airwolf Heads milled to 63cc Chambers for 10.75:1 SCR and 8.49:1 DCR
Ported Hurricane Plus intake, gasket matched to 1206 and plenum work.
Powerjection III Fuel Injection TB is rated at 950cfm. 4 x 100# injectors
Lunati Voodoo Solid Roller 0.633/.643", 247/253* @ 0.050", 0.016" Lash(Adjusted already for 1.65 Rockers)
1.65 Scorpion Rockers with Scorpion Stud Girdle
Scorpion 3/8" .120" Pushrods
SFI balancer and SFI 16# Flywheel
HEI and MSD. Fuel Injection has spark control.

In a 5 speed car that weighs a little under 3000# with me, fuel and a box of jelly doughnuts.

Thanks for any help!

[Landshark928]

Forgot to mention cam is 110 LSA 4* advanced.

[vinniekq2]

I use rocker shafts on my 434. You should consider that too for extended time at 7,000 rpm. use a rev limiter obviously. Not sure what those heads flow but you should still make over 600 hp from 6,000 rpms.
need head flow numbers at valve lift to get a better idea of HP

[Landshark928]

Yes head flow would help. Sorry had a brain fart.

[vinniekq2]

I see 649 hp plus or minus. I wouldnt try that combo with out rocker shafts myself.good luck,Im sure it will be scary fast in a light car.
dart or afr cnc ed 227s would probably be worth the extra $ if you have not yet bought heads?

[Landshark928]

Thanks! Already had the heads on my 434. Basically replaced the short block. I'll check into a set of Jesel rockers. Not sure if I can swing a grand for rockers until next spring.

Only thing I don't have yet is the push rods. Will measure this weekend to order. Intake is still at the porters. If I get close to 649hp I'll be very pleased.

[68NovaSS]

Even with the correct valve springs, I'd at least opt for a rev kit, Isky makes a nice one.

[Landshark928]

I'll check into a rev kit. I had thought they were only for hydraulic rollers, not solid.

[vinniekq2]

Rev kit can be used with ant camshaft.talk to your cam manufacturer about the springs you have and the new rocker arm ratio.The rocker shaft is good for sustained high rpms with w/e springs you need to use,,,

[Landshark928]

Gotcha. Springs were installed by Bryce at Dr.Js. I have the build sheet in the garage, I'll double check them with Lunati. Bryce told me they had room to grow if I changed rockers.