dcarter21

I have looked in a few fourms, and everyone seems to be running the tsp224 or 228. These engines all seem to be in trucks though. I'm am building a race only 4.8 to go in a 4th gen camaro.

Specs
Gutted 4th Gen
Holly mid rise carb intake
Holley 600 double pumper carb
Ported 862 heads (do not know flow numbers)
Btr .660 springs
6ls ignition
Stock bottom end
Th350 3500 stall
Foot brake 275 Drag radial car
Plan for a 100 shot n2o
3.73 spooled 8.8
Running 1/8th mile
Looking for around 400 crank hp n/a
Hoping for low 8s

JoeNova

I'd ditch the Mid rise for a more traditional style carb intake. Those Holley Mid rise intakes are laughably bad for power both carb and EFI.

If this really is a 'max effort', you might consider a bigger carb as well.

Low 8's should be pretty easy N/A with a 4.8. The 4.8 short blocks are unbelievably strong. I've heard of a couple of cars running 400 shots on 200k mile short blocks.

Here is an article where someone did similar to what you want. They used the Edelbrock Performer RPM intake (my favorite), 750 carb, cast exhaust manifolds, and a strong cam for a 4.8. 8.40s N/A, 7.20s on a 150 shot. I wouldn't be one bit afraid to put a 250 shot on a stock 4.8. Would have been enough for 6.90 in that car.

JoeNova

http://www.powerperformancenews.com/...-love-nitrous/

Sorry, forgot link.

pantera_efi

iTrader: (1)

I TOO agree that your "dual-plane" fitted intake may not be the best choice.
One reason IS the LS firing order is correct for "open" intake manifolds.
The Old School firing order 18426572 WILL work better with your fitted intake.

The choice of the ignition controller/NOS controller is of GREAT COST.
My IGN-8-LS has all the features of the combined units in ONE box, one box cost.(low cost)
My unit is perfect for drag racing as the "two step", "stutter table" PWM NOS/Fuel, NOS Retard, are ALL included.

My cam would be 246/262 116 C/L with intake lift .560"/exhaust lift 520"
The smaller intake valve of the 862 head has low weight to allow for higher RPM.
I would fit a larger carburetor.

Lance

dcarter21

Intake mnifold choice is a Holley 300-132. Not the older one 246 duration would be too much for the 9.4-1 compression ratio would it?

JoeNova

I think that's advertised duration lol.

dcarter21

Looking at the torquer v2 now. I just thought about something I know it's blasphemy to say ford on an ls1 site, but small displacement 302 have run 230 degree roller cams for years and made good power.

gametech

iTrader: (1)

I don't know what to say, because looking for 400 crank hp on a 4.8 motor is not even remotely a max effort setup. It seems like you may be looking for a streetable setup, which is an entirely different discussion.

dcarter21

I just figured I would be modest with my expectations from a small motor NA. I have no experience racing these engines. I'm coming over from sbc, and lt1 stuff. This motor will not be on the street at all. Race only. What do you think is a good goal to set. I can get the heads milled when I have the valve job done, so I can get some more compression.

JoeNova

500 flywheel on a cam only 4.8 is a decent goal. It will still handle a 150 or 200 shot on top of that. Should run a mid to high 6 in the 1/8th in a light enough car.

Tuskyz28

I would weigh the car first and go from there. Knowing your raceweight will take alot allot of guess work out.

pantera_efi

iTrader: (1)

My mistake, the Holley intake fitted is a Single Plane and fine with LS-x firing order.
I would spend money on a larger carburetor first.

Sure, to raise compression would be a great help though you do have a "high" R/L ratio which also helps with a lower static compression ratio.

Will you ever use NOS ?

Lance

gametech

iTrader: (1)

I tend to stay on the FI side of the forum, so I have never recommended this before. You need to change your rod bolts, throw in a FAR bigger cam than mentioned in the first post, use a higher stall (because you said footbrake), use a set of shaft rockers, and spin it to the moon (with maybe a bigger carb). This is, however, all guesswork until you know what your heads flow. The cam REALLY needs to match the heads. As you have noticed, there is a general lack of info about race-only NA 4.8 builds. Research old school max effort 283 or 289 builds, then add the fact that you can run more valve lift with better flowing heads. Further add that you have an indestructible (at NA power levels) block and crank.

Jason 98 TA

iTrader: (4)

Watch all the engine Dyno videos of the Texas speed camshafts on the engine Dyno 5.3l. It'll give you a great example of power gains! You can use the Dyno data to pick a camshaft to meet your combo

not to mention you'll get a tsp grind so you won't have to worry about the camshaft peeling squealing etc...

gametech

iTrader: (1)

He will still be flying blind unless he finds out good data on his head flow. Even the most perfectly machined cam in the world could disappoint if not properly matched. Smaller displacement NA builds just don't have the wiggle room that we have in the FI world.

dcarter21

Thank for the replies guys. I found a 5.3 crank and rods dirt cheap, so it looks like this may turn into a high compression 5.3 build.