[jamessh10]

currently have 1-7/8 catless to 3" x pipe
reg roto fab
just ordered full lt4 fueling, jms booster or dsx aux?
is 103 tb worth it with a reg rotofab?
just ordered all this also. cam has 32% fuel lobe.

what else do i need..
i know i can go smaller than the 4" upper it came on the PD
i'd rather have some pulley combos for when i bring it to my shop..

[KingLT1]

90mm upper with stock lower should be around 15psi.

The problem I see with standard compression pistons is you will be octane limited on 93 pump. If you want to run Pump gas then you need the lower compression pistons.

If you plan on running ms109 or E85 then you can leave compression alone. With E85 you won't have enough fuel system. Will need FIC +30 injectors, LPE pump, and Aux low side. Or go Port injection with a Aux low side or Fore setup.

You will want a Big gulp RF and 103 at that boost/power level.

[EDFHOBBIES]

I agree lower the compression a couple ways to do this..

Different pistons will make the most difference
Cometic head gaskets .079 compared to LT4 .04x
Use lt4 heads

By lowering the compression you will extend the LT4 fuel system a good ways.

Also why the 32% lobe when you can do a 38% with no problems?

It would be bad azz to see 9 to 9.5 you can get away with 10s

[EDFHOBBIES]

But to answer the question a stock lower and 3.5 to start with there only 45.00 I have a couple I may sale from when I did testing.

If I were you I would port it not for HP but so you can spin it slower to make the same hp more efficiently that you will be capped at because of compression technically if that make sense. in other words you could run a stock lower and 3.75 or 4 inch pulley after porting going from 23k rpms to 18k rpms not sure if the math is right but that's an example. I went from a 9.17 and 2.75 inch to 8.3 and the 3.0 plus I picked up 100 hp.

[jamessh10]

Originally Posted by EDFHOBBIES

But to answer the question a stock lower and 3.5 to start with there only 45.00 I have a couple I may sale from when I did testing.

If I were you I would port it not for HP but so you can spin it slower to make the same hp more efficiently that you will be capped at because of compression technically if that make sense. in other words you could run a stock lower and 3.75 or 4 inch pulley after porting going from 23k rpms to 18k rpms not sure if the math is right but that's an example. I went from a 9.17 and 2.75 inch to 8.3 and the 3.0 plus I picked up 100 hp.

brought it to my shop and he ordered all different stuff and custom spec me a cam with a 38% lobe i cancelled the above items from gpi.
i have lower compression now, or will. the motor will be going to the machine shop aug. 9th for pistons, rods, bearings, etc.
my shop said he wont build with drop ins and told me just to build it the right way.

[jamessh10]

updated parts.. still havent figured out the upper yet, says he wants to see what the 4" does first

[EDFHOBBIES]

Originally Posted by jamessh10

brought it to my shop and he ordered all different stuff and custom spec me a cam with a 38% lobe i cancelled the above items from gpi.
i have lower compression now, or will. the motor will be going to the machine shop aug. 9th for pistons, rods, bearings, etc.
my shop said he wont build with drop ins and told me just to build it the right way.

sounds like a great plan cant wait to see it!

[EDFHOBBIES]

Originally Posted by jamessh10

updated parts.. still havent figured out the upper yet, says he wants to see what the 4" does first

The pulleys are like 40 bucks so 150 bucks you can try 3 or 4 setups lol

if any are hard to come buy let me know I still have a 4, 3.75. 3.50 laying around and a 9.17 lower NIB the eforce have just a few dyno pulls.