ok, heres the deal. i rebuild 4x4 trucks from the mid 80's around here for money on the side. a lot of the time people will come to me to have engines done later on after they get over paying for my body work . but i'd like to get this next engine out of the way before the guy comes to me and asks me what i think. he hasnt had the short block redone yet so thats still something we can play with. the block is a 350 ci roller cam block. he bought some aluminum edelbrock performer cylinder heads and had them flowed they were used so i dont know what if anything was done to them, and i trust the guy that did the flow testing on them. after all he wasnt selling anything so what does he care.

Int Exh
.100 64 54
.200 122 96
.300 177 124
.400 217 147
.500 229 166
.600 232 175

intake ports are 165cc's chambers are 60cc. he also has a dual plane performer intake. he has a holley 650 carb. along with 1 5/8's mid length headers.

the gentleman is older and doesnt want anything rowdy, he actually wants it pretty tame since his wife will be driving it. he doesnt really tow anything with this truck he just drives it around on nice days and takes it fishing. he's just looking for some more punch out of it. so heres what i have come up with so far for a custom grind cam since i'm not really fond of any of the off the shelf stuff. i'm looking for about a 55-5700 red line, i hope this is big enough.

intake lobe #3188
adv. dur. 258
206* @ .050"
132* @ .200"
.538" lift with 1.6 rockers

exhuast lobe #3190
adv. dur. 266
214* @ .050"
141* @ .200"
.565" lift with 1.6 rockers

i was thinking i would have it ground straight up with a 112 lsa. the overlap would be 38* (if i did the math right) which should make it real stockish sounding? i was thinking of going to a 6" rod just to lighten things up a little while keeping costs down and adding strength. i'm too lazy right now to do the math to figure up DCR with different bottom end specs. so i'll just off the top of my head toss out 10.2:1 CR. i'm trying to get REALLY close to 9.4 out of the DCR.

i'm thinking of having it ground straight up because i dont think (at the moment) that it needs any advance being that small, and if i did it would lose too much top end. just go ahead and tear it apart... yeah i know truck engine on an f-body site. sorry but most of the truck forums dont have people who can talk on the level that you guys do in here. most people look at me cross-eyed and start to drool when they hear me making up a cam. and this is the only place i know i can come and get the kind of help i'm looking for. so give me some shoves in the right direction.

 

Why do you need a custom cam? Comp Cams makes the Extreme 4x4 cams which should be able to fit the bill. Since you are building a mid 80s truck, I assume it is a standard hydraulic cam. Check out this page:

http://www.jegs.com/cgi-bin/ncommerc...98&prmenbr=361

 

I ran you engine through Engine Analyzer Pro.

Nice torque curve. Peaked about 400 @ 3500, and stayed above 350 from 2000 to 5200.

Power about 350-360 @5500 thru 6000.

DCR I got is 7.92, with 10.2: CR. With 93 octane and best spark it should be very good for detonation.

Overlap: -16 degrees @ .050. Actual "advertised" duration, from Cam Dr. data on the 3190 lobe is closer to 275, so total overlap is about 50 deg. This sucker (pun intended) will have great idle vacuum.

These lobes are great, but they are very aggressive, and hard on valve train parts. You need to use very strong parts. All of that is expensive, and, IMO, too much money for this engine.

Just for grins, I also tried the GM ZZ3 cam (P/N 10185071):

Int = 208 @ .050 with .512 lift with 1.6s
Exh =221 @ .050 with .544 lift with 1.6s
112 LSA

.050 overlap = -10 deg. with total overlap 55 deg.
slightly less (1.5 in hg less) intake vacuum, with a DCR of 7.72.

It's tons cheaper that the XE you chose, and actually made a couple more lb-ft and a couple more hp. The curves virtually overlap. You can use standard aluminum 1.6s.

I'm not sure where you picked up a DCR of 9.4, and why you'd try to run that in a truck on the street.

Using hypereutectic pistons, .030 over and some reasonably cheap rods, and a cast crank, you'll have a very cost-effective rebuild.

My highly opinionated $.02

 

yeah i figured the lobes were very agressive and i thought maybe with the steeper lobes i'd end up with an almost stock idle. and that dcr thing was a typo my dad was bugging me at the time. i had looked at the zz3 cam which is now called the zz4 . i didnt know if the cam i had in mind would make a good bit more power than the zz3 up top or not and have a smoother idle. thanks for telling me tho now i can save the guy a little more money which makes me look better . and Josh yeah i've used 4x4 extremes thats whats in my truck but this guys cam is going to be an HR not a flat tapped and i dont like a whole family of lobes with the same lift plus the 4x4 cams are pretty frickin extrememe ramp rate wise. and comp gets away with that because 4x4's typicly dont rpm like a ****.

thanks for the input bret's dad. (Jon?) and btw sometimes when i talk to bret online he givess me cam lobes that i cant find in comp's lobe catalog can you tell me where i could get ahold of a complete list from comp? and where can i get that cam doctor prog?

 

Right, the ZZ3 became the ZZ4, and the cam didn't change.

Try www.performancetrends.com

You can download a demo of EA Pro. It's about $469. Like any good tool, you have to learn how to use it which takes some practice.

Comp's newest paper catalog, which just arrived here does have some lobes not in the old one. I believe Bret got virtually all the lobes he's suggested from the old catalog; finding them isn't always easy!

Your choice of a HR makes lots of sense to me. Good luck.

Jon

(aka Bret's ol' man)