what cam to use - Moparchat

marksram · #1 11-06-2005, 12:28 PM

i'm building a 318 for my 81 p/up 4x4 that im building for mud bogging. the block is punched out 030 over was thinking of putting in a cam spec for a 340. i need lots of low and mid range torque and hp. i'll be using the orignal
4 spd trans. in the class i'll be running in i need to use oem carb. do you
think a thermoquad would do it? was thinking of having the heads shaved to
boost compression. any advice would really help.

TK · #2 11-06-2005, 02:04 PM

Quote:

Originally Posted by marksram

i'm building a 318 for my 81 p/up 4x4 that im building for mud bogging. the block is punched out 030 over was thinking of putting in a cam spec for a 340. i need lots of low and mid range torque and hp. i'll be using the orignal
4 spd trans. in the class i'll be running in i need to use oem carb. do you
think a thermoquad would do it? was thinking of having the heads shaved to
boost compression. any advice would really help.

If you can get your heads shaved, you may want to get bigger valves too. (I think Rumble just said this in another thread?) 1.88/1.60's in 318 heads do wonders.
As far as the cam? A 340 cam is not a great torque cam IMO, they run OK, but it is a older design.
IMO, a cam about 270 Duration, with 480-500 lift would do you good, with your 4 speed. (Engle cams look appatizing, along with Lunati................)
Possibilities are endless!
Talk to your machine shop about milling and such, they should know what you need.
Thermoquads are great carburators! (I dont like them, but thats my opinion) And should do great WOT.

marksram · #3 11-06-2005, 10:34 PM

thanks for the info. do you know if holley made carbs for mopar oem?
also how can i find out the gear ratio in the diffs if there isnt a tag on them?

rumblefish360 · #4 11-07-2005, 12:23 AM

Holleys came on Road Runners. After that, I'm not to sure.
The ratio can be found in the ring gear. I'm not a fan of pick up the car and count rotation of the tires to the driveshaft. It probably hasn't had a rear end gear fluid change since it was new anyway. What better of an excuse.
Go here for a gaggle of MoPar parts and choice of cams you can research;
http://hughesengines.com/

TK · #5 11-07-2005, 02:06 AM

What exactly are the rules on the carb?

marksram · #6 11-08-2005, 12:41 AM

well in the class i'll be running in, ican only have 2 engine mods. one will be
headers the other will be either a carb or ign system. thats why i want to shave the heads to boost compression and a cam that wont have a noticable
idle but will give me good hp and torque. otherwise i will have to run upper class and well maybe when i can afford to build up a big block.
thanks for the help.

TK · #7 11-08-2005, 04:05 AM

I would run a Comp 260/260, you cant hear it idle.
Headers
And any 4bbl carb. Hell, I would even run a 2bbl off of a 360.
Raising compression is always good!

marksram · #8 11-09-2005, 01:24 PM

they say i can have a minimum of 14 inches of vacuum at 800 rpm if
that helps narrow the size cam down.

rellik eeb · #9 11-09-2005, 10:09 PM

Id give a custom grind cam a chance here, dont just stick a cam in it, tere is lots of factors that can effect engine vacum compression, and camshaft overlap are the keys here. I take it you can run a stock intake only. Id go for a 73 up 360 style intake a thermoquad, do the hedders, and run stock igntion. It needs some tweeking but very reliable and just as high tech as MSD Pro Billet with its Magnetic pickup. A recurve will do wonders. Id find a set of 308 or 302 casting heads. They will make great lowend torque, just put stock 360 valves in them, no need to go 2.02 or anything. That may hurt lowend power anyway. Have them milled about .050. Run the thinnest head gasket you can find, not sure if Mopar makes a steel shim like a offered for Big blocks but that would be my choice, givem a good coat of copper spray so the dont weep water also.

rumblefish360 · #10 11-09-2005, 10:33 PM

Quote:

well in the class i'll be running in, ican only have 2 engine mods.

well then, no body will notice a chome or gold box painted black or the black MSD wires. How about them iron W-2 heads. Only those who know and are searching can find them. He he he he he.

Custom cam and headers. Good idea. Very good. Good thinking rellik eeb!
Oh, also, yes a T-Q jetted right will do it.

marksram · #11 11-10-2005, 11:00 AM

cool, thanks for the tips! keep them coming! will a windage tray for the oil pan
help with hp?

rumblefish360 · #12 11-10-2005, 11:04 AM

Yes, on the big end. 15 HP. There stock equipment.

Open up the louvers a bit. A Viscous fan from MoPar is worth another 15 hp. Again, stock equipment.

marksram · #13 11-18-2005, 01:52 PM

hey! i just ran across a 360 w/stock 4bbl in a 80's 3/4 ton truck supposed to have original 70-77,000 miles on it for $300.00. what do you think about building it instead of the 318? if so what should i do to it? HELP!!

rumblefish360 · #14 11-18-2005, 02:57 PM

The T-Q needs a minor mod. The primary ventuiry has 2 holes in the foward facing wall. Plug them with JBweld. The rear top potion of the carb has a electric hook up for a vent. Take off the top and remove the rubber disk on the metal tab. This vent the carb at all times. Theres no extra pressure build up this way.
I think you'll like the 360 better. It's 42 cubes bigger. Mostly in stroke which equals torque.