Seagram's 72

iTrader: (2)

I got my car going with a fairly stock 6.0 2003 LQ4 over the summer, here are my current specs:

1972 Chevelle
200-4r tranny
-factory everything except reverse manual valve body
12 bolt posi, 4:11 gears
Edelbrock Performer LS1 (Dual Plane) Carburated Intake
MSD Ignition box for carb’d LSX
1” 4 hole poly carb spacer
Holley 4160 carb, 750 vac secondary
-8.5 power valve
-74’s or 70’s in the front for jets
-Plate in the back (no dual metering block style)
-Black cam pump
-Heaviest or second to heaviest secondary spring
(it’s been a while since I tuned this so I forgot the exact specs.)
Engine:
2003 LQ4
-Stock Long Block (cam, bottom end, heads, etc.)
-Truck Manifolds

This set-up is very reliable and has great bottom end. This winter I plan on doing a few bolt-ons to boost the power.

My goals are to stay on a budget, keep the factory short block, keep the reliability, and increase the low torque/ overall power curve. I am big on spending $ in the right places to achieve the appropriate power level. The $ to HP ratio!

I have a few questions for what I am trying to do:

-Cam
I was thinking of going with the GMPP Hot cam as seen in the car craft budget 6.0 build (P/N 12480033
), but am open to suggestions. Something to help boost the bottom end and keep the power increase going throughout the torque curve. Any recommendations? If I do go with a cam and keep the stock heads, is it worth upgrading to LS6 valve springs?

-Heads
Right now I have the aluminum factory 317’s. To stay within my goals is it worth it to keep the 317’s, mill the 317’s, or get a set of 243’s? Again, I am going for the best HP:$ ratio. I have always boosted CR to gain HP, but still want to keep it streetable and also use my factory pushrods. Would it be worth it to go to a set of 243’s? If it is, would it be worth it to get any head work done, I.E. milling or port/ polish?

-Carb
Right now I have a 4160 vac secondary, is it worth it to upgrade to a dual metering block vac secondary, or even a double pumper?

-Nitrous
I may run this next year, but only a 100-125 shot for fun.

-Any other bolt on suggestions?

I am taking the car to a chassis dyno for a tune come spring so I am hoping to boost the HP level with what I can before the tune. I am new to Gen III/ IV small blocks, let alone a carb’d one, and want to unlock the all the power I can with a few bolt-ons.
Thanks

ZONES89RS

iTrader: (25)

You sir, are dead on track to a reliable steet car that can do the nasty when it needs to be done. Head wise, if you want to be able to stick with mid grade, then just mill them down .030 and slap it back together. I would however go with the Vic Jr single plain, will work way better with the nitrous and the small amount of low end torque is well made up with top end gains.

Seagram's 72

iTrader: (2)

Thanks, if I sliced the 243's down .030", could I use stock pushrods or no? Any other issues to worry about with having the heads milled down?

ZONES89RS

iTrader: (25)

.030 is about the furthest to go. But the compression you will have with those will require 93 octane, if you are not looking for max power, i would stick with 317s and mill them .030 and save money VS buying heads, my Trex cammed 6.0 LQ4 with 317 milled still likes mid grade, but i will be going with the ported 243 later for max power and performance from the cathedral ports.

NemeSS

iTrader: (127)

the 243 and 317 share same intake/exhaust port design
but different size and design chambers.
mill the 317s .030, and use a LPE GT11 cam with patriot dual springs. final pushrod length needs to be verified. but do not use stock pushrods. get some .080 wall in whatever size is needed.