how can i make power with a 4.2 - Page 3

franked · #41 (**permalink**) 02-09-2009, 09:35 AM

I DO have emissions, and I already have the Howell EFI, I would like to do the head swap to get some more power out of my 4.2, I have to have EGR. Need to know the right exhaust (OEM, or CARB# parts, California air resources board ) and the best intake with EGR for power.

fullhouse · #42 (**permalink**) 02-12-2009, 07:43 PM

well, it is really depends on your vehicle. its hard to match up those intakes to know whats the best.

chaos.258 · #43 (**permalink**) 03-21-2009, 11:18 PM

This is what I have done to get power out of my 4.2 without doing any damage: Offenhauser alum. intake. Holley 390cfm carb. w/1" Mr. Gasket spacer. Pacesetter headers. CRT Juicebox w/8mm wires, 35k volt coil, Bosch plat-plus plugs gapped .045. (ever hear the term: purr like a kitten?) More horsepower, lower than stock emissions, and better gas mileage. This job is finally complete and is a night and day comparison. The total cost for this project was less than $1100. I can not say for sure if this will pass California emmisions?

Who Cares?

franked · #44 (**permalink**) 03-24-2009, 12:13 AM

First of all, I care, I have to register it here in california where I live, second I already have the howell fuel injection, any manifold or exhaust has to work with that. It runs pretty well, just not really strong up a hill on the highway. I can live with the power it's got for now, I may get the 4.0 head at some time, or just go to a chevy 305/350(TBI, of course)

chaos.258 · #45 (**permalink**) 03-31-2009, 09:10 PM

Quote:

Originally Posted by chaos.258

This is what I have done to get power out of my 4.2 without doing any damage: Offenhauser alum. intake. Holley 390cfm carb. w/1" Mr. Gasket spacer. Pacesetter headers. CRT Juicebox w/8mm wires, 35k volt coil, Bosch plat-plus plugs gapped .045. (ever hear the term: purr like a kitten?) More horsepower, lower than stock emissions, and better gas mileage. This job is finally complete and is a night and day comparison. The total cost for this project was less than $1100. I can not say for sure if this will pass California emmisions?

Sorry about the cal. emissions crack, but the juicebox alone will lower your emissions, improve mpg, and give you a more reponsive accelerator.

palehawaiian · #46 (**permalink**) 10-22-2009, 01:07 AM

you can gain about 40 horespower and 3-4 miles to the gallon if you get a newer intake of a 4.0 and have the channels filled in the right spots... Its an easy swap and you can get the 4.0 head off ebay ready to install for like 350. Look here to buy it
and here to install it

Hope this helps

54cj3b · #47 (**permalink**) 10-22-2009, 11:40 PM

fuel injecters will help boost power the most eliminating most of those vacum lines at same time

franked · #48 (**permalink**) 10-23-2009, 01:01 AM

I like the header in that article, from an 88 Cherokee, apparently. what do I do for intake, and will I still pass emissions in CA without the EGR, or does that setup have that?

carnuck · #49 (**permalink**) 10-27-2009, 12:02 AM

Quote:

Originally Posted by franked

I like the header in that article, from an 88 Cherokee, apparently. what do I do for intake, and will I still pass emissions in CA without the EGR, or does that setup have that?

If you use the stock Cherokee or Comanche ('87 to '90 4.0L) intake and exhaust manifold, they have the egr already.

franked · #50 (**permalink**) 10-28-2009, 01:04 PM

Sweet!