Thread: BBC 468 Build questions

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Ok guys, I need some help. I am building a 468 for my Jeep and need some insight. I have a few parts questions and would like some CONSTRUCTIVE remarks. No brand bashing without some meat and potatoes to back it up.

1978 2 bolt Block w/ 781 heads:

All bearings are Clevite H series coated. High flow oil pump and oil bypass delete.

Speed Pro Powerforged ZL2465F60 Pistons
http://www.summitracing.com/parts/TRW-L2465F60/

Total Seal Maxseal rings M2090-65
http://www.summitracing.com/parts/TSR-M2090-65/

Lunati Voodoo Camshaft 60202LK w/ suggested springs, retainers, and locks. Along with Cloyes double roller timing chain, cam button, and cam plate.
http://www.summitracing.com/parts/LUN-60202LK/

Of course a seal kit from Sealed Power
http://www.summitracing.com/parts/TSR-M2090-65/

RPM Air Gap intake
http://www.summitracing.com/parts/EDL-7561/

Holley 750CFM Double pumper for street
Propane for playing in the dirt (dual fuel hat)

I am looking for advice on a couple things. I am wanting about 10:1-10.5:1 compression. I am pretty sure I am gonna have to mill some off the heads to get the compression up. Anything to look out for or any idea on how much I will have to take off to reach my goal? And will Positive Valve Guide Seals work with these heads, or do I need to have them "fitted"? Also, I have read alot of good about the gapless 1st rings, but some bad. I am looking at them from a longevity standpoint. Not from the myth that they give you more power. I have read they are good from the standpoint of leak down staying more consistent over a period of time. I will not be reving this motor past 5500rpm, but it will be exposed to lots of off-camber, banging around, 8 hour a day thrashing. Any other suggestions? Critiques?
Thanks,
Clay

I have the same pistons and i was only able to get 9.5:1

Why do you say that? Are you zero decked and do you have your heads milled or what?
Clay

I would leave it around 9.5 to 1 with that camshaft. You will have lots cylinder pressure with that camshaft timing and 10 to 1 compression. You may need to consider higher octane fuel. I like the 781's...good heads, usually about 119cc.

you might consider going with a slightly smaller cam, maybe around .510 or .520 lift, keep your compression ration you come up with. seems a bit overkill if your not revving over 5500, plus you want torque torque torque, down low in the powerband if your going off-roading. I'm assuming thats what you'll be doing with your jeep aside from daily driving. Comp has an Extreme Energy 4x4 series that has a cam perfect for you, Hydraulic-Great mid-range power, largest cam for stock converter. Good for heavy towing with 4.10 gear. 218/226 duration .505/.515 lift. Probably has a decent idle too. But that my two cents. I'm building almost the same motor, but its going in a street driven 84' shortwide Chevy that will see some track time. I'm milling and decking but i'm stuck with flat tops so I have to, just to hit 9:1. My block is a 4 bolt, with 781's, 2.19/1.88 valves, Edelbrock 2.0 manifold and a Demon 800 double pumper. I still can't decide on the cam but probably no more than .550 lift, should be a nasty little torque pig with lots of grunt, good luck with your build

Trust me I know about down low torque for off-roading. But it is all relative, since I come from a "mild" SBC in my last CJ-7. As much gearing as I have I am rarely below about 1000rpm. I am running a 3.77 1st gear, 4:1 low in the t-case, and 4.56's in the axles as of now. I will be running a 6.32 1st gear, 4:1 low, and 5.89's by the time summer is out. After talking to my machinist, I am probably going to just have them square up the heads and block and call it a day. He say that with those pistons and how my motor looks now I will be at 9.66:1 just squaring it all up. I was told to get as close to 10.5:1 to get the most out of the propane, and then just back the timing out to get it to burn premium on the street. That is the only reason I was looking for more. I do not mind having to run high octane fuel, I did it for 4 years with my CJ-7 as the SBC in it was at about 11.5:1. As for daily driving... it gets taken on the road on nice days around town and to the lake. Anywhere else it typically gets put on a trailer due to the gearing.
Anything else I should think about?
Thanks again for your time,
Clay

Here is a few photos from the last time it got bashed on...

This is what cam I'm running in my 468 & it's just about the same price!

http://www.compperformancegroupstore...ARKIVCAMHFT4X4

So do you mud to or just rock crawl??

Rock crawl only. I did the mud thing in High School, I dont like to play for 30minutes and clean for 3 hours. That and we don't have alot of places around Texas for mud.
Clay

Originally Posted by jeepman1320

Rock crawl only. I did the mud thing in High School, I dont like to play for 30minutes and clean for 3 hours. That and we don't have alot of places around Texas for mud.
Clay

So your putting a BBC in a rock crawling jeep.........why? Not to be an asshole or anything.

Why not? Maybe because it is different, everyone runs SBC's or LS motors... If you saw the whole buildup of the jeep it is going in you would understand this is not your typical Scrambler. Not to mention that a 4.2 straight six even geared will have a problem turning the 42" Pitbull Rockers that are going on it. Rock Crawling ain't always just Rock Crawling, sometimes you need to get it.
Clay

Originally Posted by jeepman1320

Rock crawl only. I did the mud thing in High School, I dont like to play for 30minutes and clean for 3 hours. That and we don't have alot of places around Texas for mud.
Clay

Guess you've never been to Michigan!

Originally Posted by jeepman1320

Why not? Maybe because it is different, everyone runs SBC's or LS motors... If you saw the whole buildup of the jeep it is going in you would understand this is not your typical Scrambler. Not to mention that a 4.2 straight six even geared will have a problem turning the 42" Pitbull Rockers that are going on it. Rock Crawling ain't always just Rock Crawling, sometimes you need to get it.
Clay

Weight is not an issue i guess!! Most rock crawlers try to cut weight.

We don't try to cut weight around here. Competition/buggy guys want em lite. Recreational/full bodied guys don't care. We care more about armor. I run 1/4" corner guards, 3/8" skid plates and rocker guards, and all the tube in the cage is .188 wall. It came in at 5200lbs with 37's and a straight 6 jeep motor and half a tank of gas.
Clay