Full engine upgrade

[agrexbo]

Have a 1991 Explorer sport 4.0L. It is going to get some major upgrades in the near future. I am searching for a mild RV cam, any ideas which one and where I can purchase? Any preferences on CPU chips for an upgraded cam?

 

[Creager]

410 comp cam if you want more torque (and street legal)

422 comp cam if you want more HP (and not street legal in most places)

if your gonna go along with bigger cams you are going to need everything

i would personally go with

1) 410 cams w/ custom length pushrods
2) ported polished heads
3) full floating rockers
4) dual valve springs
5) hedman headers
6) Custom Chip from BamaChip or SCT

with our year explorer a chip is useless unless you get all that internal work done

 

[huskyfan23]

A custom chip is not useless without internal work.

Your list looks good, though I'd get JBA coated headers.

 

[410Fortune]

On top of everything listed above dont overlook head porting.

IN order to make good power from the OHV 4.0L the heads could use alot of help. The upper and lower intakes can e gasket matched as well, and or ported.

Then


MAS, TB, intake, exhaust, gears, and you will be set

Of course the chip or PCM reflash should be done last, preferably with a dyno available so it can be dialed in


Plan to spend alot of $$$ to build a 4.0L

 

[Creager]

exactly, head porting is probably the outstanding best mod on that list

if just ported the heads and just rebuilt everything with stock intake, headers, and cam... you can probably get that stock 160 hp to 200... no joke

and again a chip is useless (as in not worth the money for the gain) with stock internals, unless you plan on spending $2.10 a gallon for premium.

a chip on the stock 91-94 OHV only adjusts the Air/fuel curve, for 93 octane

 

[Heavymentill]

422 comp cam Not recomended with auto trans.

 

[Creager]

yeah it was mentioned that you cant use 422 cams on the Auto tranny.

a c4 will do the job fine aswell as get rid of that peice of crap stock auto tranny (a4ld)

i have the Mazda 5-speed... i'm pretty sure it could handle the 250-300 hp from a completley built 4.0 motor... anyone know?

 

[410Fortune]

You are dreaming, the Mazda 5 speed is allright, but its not gonna take 250 HP....

 

[boominXplorer]

is there any reason you are set on building the 4.0? A 5.0 is ALOT cheaper to build and you can put alot of beafy trannys behind it. Thats just a thought

 

[monkeydude3]

the 5 speed manual ain't worth crap beyond OEM.... my explorer is stock and mine blew towing a trailer at 50 mph cruising speed...... in my opinion... why go through the trouble of making a vehicle like this incredibly fast? Save the $ and get a mustang or something of the sort built for speed...

 

[little x]

What valve springs would you suggest, where can I find them? I'm about to put in a 410 cam with smith bro's push rods.

 

[Creager]

dual valve springs... Crane Cams, or Onan Cams, Comp Cams... they all should work...

you got to school in boone?

 

[little x]

Yep, ASU.

I read where you could use Comp's springs (part # 988-12) those are $78. Is that $78 for all 6 cylinders, or $78 per cyl.?

And then you need to use Crane spring retainers (part number 99947-12). But I can't find that part on their web sight. Do I just need to call them? Does anyone know how much the spring retainers are?

Would it be cheaper for me to just use Crane springs? Does anyone know a part number? A price?

Again, this is for a Comp 410 cam, smith bro's push rods