2.8l v6 more power needed (got carb, manifold, headers)

[ilandaze]

my brand new rebuilt 2.8l v6 just doesnt have the power i want. right now i have an holley 390 cfm 4 barrel carb on it with an edelbrock performer manifold and a set of pacesetter headers. the carb seems to be tune well and the car runs fine. it just give me enough power. it's sitting in an 84 jeep cherokee. just wondering what else i can do to get it going. considering putting a cam any recommendations. also will changing my diff gears make a difference in power b/c i have 31" tires on it and stock like 26"?

[sharkey]

you seffinitly need some different gears in that thing, something like 4.10 would work nicley. btw, what year is the truck and is it the original motor???

if you are looking to spend a bit of money, do a full rebuild on it. throw some higher compression pistons in. something like 9.5:1 compresion would be about right, although you will need to run better gas (likely 89 octane would be fine).

was your truck originaly fuel injected??? if not, then a good idea would be to fine heads from an 85+ fuel injected engine as they have larger valves (1.72int, 1.42ex vs 1.6int, 1.3ex) and have them ported. there is a lot of power hiding in those heads, and being you have the intake and exaust work done, its going to respond well to porting.

as for a cam, a lot of guys are happy with the comp cams 260h, but its a high rpm cam. you may want ot get the cam that goes with the intake you have, you will likely get the best results. http://www.edelbrock.com/automotive/index.html the cam at the very top.

[geoffinbc]

Ok a Jeep what do you use it for? I would asume street and mild off-road. Well go with a high lift short duration cam with a midle of the pack lobe seperation. This will give you killer torque but will die at 4500RPM. But I think the tradeoff should be fine for your application.

Definitly go and find you self some HO heads and get them ported out. Do the same to your intake.

With a cam and intake you will be quite suprised.

[ilandaze]

its not the original motor but a rebuilt one. im looking to rebuild my original motor. once i get closer to smog time im going to rebuild it and use that for my performance motor. i just had the stock head redone for cheap on the original motor. it an 84 jeep cherokee originally carbureted. was thinking of the edelbrock cam to match to make it a total package or whatever combo they have. betterthanyou what cam did you have in mind thats exactly what im looking for. for my original engine can u recommend some piston and rings, crankshaft journals, and whatever else id need for a rebuild. jeep has a 4inch lift

[oil pan 4]

Do you know what year the moter is from?
There are several different varriations of the 2.8 out there.
You can get a larger cam, I wouldn't go as big as the one I have.
But there are some on the summitracing site that would be good for a truck appication.

[mopowr79]

First off. Back in the day (about 20 years ago) Hot Rod magazine (or one of the others, maybe Carcraft) built up a 2.8 carbed motor. They used a variety of carbs on the Edelbrock manifold and found the best bang was a Holley 5200 350 cfm carb. The 4 barrel hand stand off issues and caused the engine to bog, even the 390 cfm 4610. Now another option would be to pick up a complete 3.4 FI motor from a later model Camaro or S10 and install it, make sure to get the computer and assorted peripherals. There was a guy on Jeeps Unlimited building a 60 degree V6 powered Jeep called The Warrior. He was boosted and running about 300 rwhp. A last thing to note is that 60 degree 2.8's like a bit of backpressure, so headers are fine but dual exhaust is likely to hurt your overall performance. A good 2.5" single exhaust will do better overall. mopowr79

[ilandaze]

its a chevy block and i do have a single exhaust 2.5" catback. should i get a straight pipe instead of the catalytic converter. thinking of the edelbrock cam. i got the holley 4160 390 cfm.

[geoffinbc]

Go with any cam maker you wish. If you do use it for offroad then get one advertised as an RV/Towing cam. This will give you the big torque.

If you are getting ready to swap in a new engine in the future than I have to advise you to get a 3.4L. It will put a grin on your face from ear to ear. The increase in performance is amazing.

[ilandaze]

i know about the 3.4l. but i got my 2.8 for dirt cheap so thats y i have it in there right now. so any input about rebuilting my stock block.

[geoffinbc]

Stock block? From 84? I would ditch it. With small journals and small valve heads. Poor oil pan seal and main seal it isn't worth the time. Honestly you could probabally sell it as a core and at least pay for a descent chunk of a 3.4L

[mopowr79]

My bad, Holley 4160, not 4610, just woke up this morning and posted. You might get good results with a Weber dual 38 as well. Basically a 32'36 with linked primaries and secondaries. The 2.8 doesn't need a lot of cfm. If you get a chance, check out Warriors ride on Jeeps Unlimited. mopowr79