[BigEd36]

Ryan, with the compression ratio you'll want to keep your cam below about 270* advertized duration or 218* @ .050".

[ryan v]

Thanks for the help i'm probly gonna get the elgin 1065pk cam with the first kit.
Any other advice you guys would like to add?

[ryan v]

well finally got the motor tore down and found out it spun a main bearing. luckily i had a extra block sitting in the shed. I've figured out what rebuild kit i'm gonna order i just can't decide on wich cam to order with it. I ended up getting a set of 186 double hump heads to run instead of the 993's.
The cams i'm looking at are these and would i need to run a stall converter?
Elgin #CL1065PK 2000-5000 218/218 dur @ 50 .458 .458 lift

Elgin #CL1785PK 2200-5200 rpm 218/218 dur @ 50 .450 .450 lift

Elgin #CL1784PK 2200-5200 rpm 228/228 dur @ 50 .480 .480 lift

Any advice on wich ones you guys would think would be the better cam?

[cobalt327]

Originally Posted by ryan v

Would getting a 2000 stall converter open up my cam choices any?

The stall speed of the TC needs to be set to put the engine right at the torque peak at max stall. You should use more stall than 2000 rpm even w/the smaller cams.

Those tall tires cuts way down on the effective, or overall, gear ratio to the point that either more gear will be needed or a higher stall speed TC or BOTH, especially as the cam duration/overlap increases and the bottom end power decreases with it.

To put tire diameter vs. overall gear ratio into perspective, your 4.10 gear w/35" tires is about the same as a 3.5 ratio w/30" tires.

[ap72]

Originally Posted by ryan v

Elgin #CL1065PK 2000-5000 218/218 dur @ 50 .458 .458 lift

you can get by on a stock converter with this cam, but more stall would be nice. keep your stall speed below your cruise RPM though with those heavy tires your trans will already be overheating.

[BigEd36]

Ap72 brings up a good point that should be mentioned. Automatics and high stall converters make a lot of heat, excess heat is a big killer of automatic transmissions. You should run a transmission cooler to prolong the life of your trans and converter. The stock cooler in the radiator just won't get the job done in an application like this.

[cobalt327]

Originally Posted by ryan v

I'm not really worried about street performance because this truck will probably never see the road again.

Originally Posted by ap72

you can get by on a stock converter with this cam, but more stall would be nice. keep your stall speed below your cruise RPM though with those heavy tires your trans will already be overheating.

Any/all offroad mud truck/competition/WFO running/etc. need axillary coolers, even w/a stock stall speed TC.

Engine cooling system needs to be fully adequate as well. Just two of a hundred things that need to be addressed.

[ryan v]

it already has the auxillery cooler for the tranny. Will it make any difference to cam choice if its always gonna be ran in 4 low? I also had a question about the cams that have the same power range but the lift differs why is that?

[BigEd36]

Originally Posted by ryan v

it already has the auxillery cooler for the tranny. Will it make any difference to cam choice if its always gonna be ran in 4 low? I also had a question about the cams that have the same power range but the lift differs why is that?

Ryan, the rpm power range is mostly determined by the duration and LSA (lobe spacing angle). More lift will enable an engine to make more power, but where in the rpm range that power is made will be determined by the duration and LSA. As a rather extreme example there are oval track "lift rule" cams for classes that are only allowed a certain amount of lift. If you have 2 cams, one with .420 lift, one with .480 lift, both have the same advertised duration, .050 duration, and LSA, the cam with .480 lift will make more HP than the .cam with .420 lift, but both cams peak torque and peak HP levels will be about the same rpm. This is why oval track lift rule cams are somewhat popular for budget builds with Vortec heads. The Vortecs only allow about .450 lift without the modifications for increased lift, but they're designed to breath best at moderate lift. Using a lift rule cam you can still get the benefits of increased duration. If you do a search for F-bird'88, he has posted a recipe for budget 350's with Vortec heads using Isky .450 lift rule cams that have some very stout HP and torque figures.

[ryan v]

Thats kinda what i figured they had the lift difference for just wasn't sure. So i'd be better off getting the cam that has more lift if my heads can handle it?
Sorry for all the questions i'm just trying to get as much info as i can before i order the kit. I got burned on the last motor by listening to people who supposedly knew what they were doing and spent more money than it would have taken to rebuild the motor completely.