your new so you never got to see or searched for all the data Jon posted a few years back.
When the suggestion of an alternate fire cam came up from Jon years back, some thought it was the "solve all out issues" fix and other saw it as a bandaid (me as one of them) and others just flat didnt think there was enough evidence to say it will fix the issue. For a long time, when places were making and selling the cams for twice that of a SF cam, people were saying all their crank issues vanished and this would stop the problem. I did not agree, i and many others still felt it was a bandaid for the real issue and was really wanting to see someone look into it and fix it. then the first crank broke with an AF cam.... it was a used LB7 crank and then it was suggested you HAVE to buy a new crank if you want to be sure it lasts. ok cool, still a bandaid imho though. So now if you have to buy a crank AND a cam, you're getting into the 2k range (at the time, closer to 2500,3k). time went on and things popped up here and there of cranks breaking, mainly used ones, with AF cams. Some will not post on this forum that have broke them with new cranks. they are out there, i know this for a fact.
then Callies came out with their crank using narrows rod journals to increase the meat on the journals of the crank. it has been said and factual shown on here, the main issue arises in the diameter of the crank journal. it is too small and does not have enough overlap of the mains to keep issues at bay. Guy and i believe Pat both explain this. This leads us to GM making the changes they did to the crank you see in the L5P. they changed it for a reason and its not just cause im sitting here implying all this is the reason, they are not dumb and there are a few people on this board along with me that have connections. They increased the journal diameter to help eliminate the issue. this is a tired and trued fix and is based on engine engineering. why didnt GM change the rod journal initially? well at 300hp in a lb7, ill bet you the issues never showed up and why would they care about people pushing the hp out of it we are now? then the LBZ came and GM decided to take weight from the pistons but add it to the external balancer, increasing the chances of the crank breaking. Then we start seeing a little trend happening in our own poll. GM keeps upping HP to keep up in the market and next thing you know, HP levels are coming close to 500 and now they must do something about some old engineering they are running off of.
It all comes down to budget in the end. if you want to put an AF in and a narrowed rod journal crank, go for it. if you are limited and want 1000rwhp, id do a NRJ crank before a cam as you can get the HP without the cam and still be reliable in the bottom end. If you dont want to drop the coin on a crank but want sub 1000hp numbers, it comes down to what you want to do for the cam. it can be a toss up if the cam will really help keep it together or not. im sitting on 45k miles, 600+ hp towed on and ran every time i drive it, and still on delipped LB7 pistons with 213k total, and a used lb7 crank with 213k total.
If the AF cam was still double that of a SF cam, id say there is a valid argument for not changing it depending on circumstances but they are so close to the same now, just comes down to budget and theory.
i will still say, the crank is our issue and ill never say the fix is a new stock crank and AF cam. Dale isnt far off the callies cranks with NRJ cranks may still fail, is .040 on each side enough to hold up? Kidturbos boat setup will be a true test to it and i very much look forward to seeing it. Personally, id like to see if the new GM crank will retrofit into 01-16 block with a little work and new rods. if it will, that will be a hell of an upgrade.
Case closed :thumb:
