She lives again! New cam for '88.

Got the R&D Stage 1 cam into Big Bird, my '88 tan F-250. This motor currently has a stock '88 bottom end that was evidently rebuilt around the year 2000, heads that Typ4 clearanced for me, the R&D cam, exhaust piping from a Banks Sidewinder kit(crossover pipe was copied and built by R&D after the original broke), a lowest-bidder Ebay intake piping kit, and the most important part, my S360 turbo with .63 exhuast housing.
The great part of it is that it's definitely got some power, and under deceleration it's nice and smooth - no ticking/clattering. So the valves and pistons have good clearance and everything's working right.
Currently, it needs a little advance up high - I'm guessing the better flow characteristics of the new cam are probably reducing intake temps due to less restriction. I also am seeing a little less boost from the turbo, but still... I've gotten it up to 24 PSI unloaded in 4th.

[@matthewmichiels1272]

Outstanding congrats always good to see an idi getting it done

[@1997cr80r]

I think you would be more happy with a .83 a/r the small housing is probably causing really high drive pressure

[@MacRobbSimpson]

I have one handy, off that turbo. It didn't do ****. I could barely get it to spool above 10 psi, and very lazy at that. It was so bad that I swapped back on my TE06H for quite a while; that, I could push to 20, but it was seriously out of it's effeciency range. (Like, I bent a pushrod flooring it up a hill type of massive backpressure). This one with the .63 housing... *feels* a ton more open. Spools nicely(though not as well as it originally did with an earlier motor / no cam), and EGTs seem to be much better than the TE06H.

[@1997cr80r]

@@MacRobbSimpson maybe try a .70 .63 just seems pretty damn small to me without a wastegate unless you have one

[@MacRobbSimpson]

@@1997cr80r It seemed very small to me too - everybody told me .83 was 'perfect' for this application. I just never had luck with it. I'm quite happy with this setup, actually. I don't get 27 PSI till 2800 RPM, which as far as I can tell is still in the efficiency range. Sure doesn't feel like it's being pushed -- not like the te06H did. I'm going to add an exhaust backpressure sensor one of these days and see what my boost to drive ratio is.

[@1997cr80r]

@@MacRobbSimpson everyone tells me .83 on my 6.2 but I have no idea seems big for a 6.2 but who knows. I was gonna do a s257sxe on my 7.3 idi with a .70 housing

[@TwinStickFilms]

Can you get more exhaust video of that cam?

[@steveanderson2264]

I'll trade you speedo gears I just put 355 gears in my 410 truck

[@ChiefLightning9]

So is it faster or slower with the speedo error

[@MacRobbSimpson]

It reads low. So, when I'm travelling 60MPH per my GPS, it's reading about 50. 45MPH was around 37 on the speedo.

[@FueledAddiction]

@@MacRobbSimpson how much boost can you safely run on a studded 6.9 before the rods go

[@MacRobbSimpson]

@@FueledAddiction The rods won't go, it will still be the head studs, at around 20 psi of boost. Close to the 'instant lift point' of a stock 7.3. Probably 300RWHP range? You'd need to upsize the threads to 1/2-13 and use 1/2" ARP studs to keep the head clamped well enough. Rod failure point should be close to 400-450 RWHP.

[@FueledAddiction]

@@MacRobbSimpson is it really only 20 psi even if you put arp head studs? That seems to low

[@MacRobbSimpson]

@@FueledAddiction Go look at bolt clamping force - ARP studs are what, 200,000 PSI? and 7/16" diameter=30000 lbs of force. Stock 7.3 bolts are around 153K psi, and 1/2" diameter So, 30000 lbs again. (pi*r^2*psi). Now, the actual numbers are probably less - the minor diameter of the thread is the diameter that matters, which is less than the 'nominal' dimension of the bolt, but these should suffice for a basic back-of-the-envelope number. And, I've also seen a guy blow a 6.9's gaskets using ARP studs and a standard stock-type turbo. I have the short block out of that. The 7/16" bolts are just too small for pushing a bunch of force into.