ok so i have a stock 74 model truck 460 with home ported d3ve heads and a 500 lift summit cam thats all , plus a s475 borg warner turbo with the 96x87mm exh.wheel and 1.32 a/r exh housing with one side of the housing blocked off because it wouldn't spool up quick enough with a stock stall truck converter and c6 , well now that it spools way better it is hitting like 9-10 psi in 1st gear instead of 4-6 psi in the midle of second gear at 10 psi it should be making about 500hp and 800tq at the flywheel and it will break loose from a 40-50 mph roll with a 300 gear and a spool so since it is a stock cast piston cast truck rods and cast crank setup what will break the bottom end is it horsepower torque or rpm or a combination maybe someone with alot more expereance than me can tell me what i should be worried about right now i have the rev limiter set at 5800 rpm and i am pulling 1*of timing for 1psi and have my base timing set at 15* with the distributor stock not locked . a/f ratio is high 10's under boost the car wieghs aroud 3100 i think thanks for any info

 

Josh, I'm a new guy to the "boost world", however I do have a bit of 460 knowledge (both N/A & Nos). The pistons are your weak spot for sure. The block is non-issue, the stock (car) rods are fair (you should have the better "football" rods if it's truely a "truck" engine). The stock crank seem to be able to take a bunch of abuse. I would leave your RPM limit about where you have it. The valveheads have been known to "pop" off some, but I wouldn't think that would be a problem with the RPM/spring pressure your dealing with.
Just from doing the research I see a couple things that make me ask questions about your build.
A 460 cubic inch engine would seem like it should be able to spool that turbo no problem...Could you have a leak or Two on your hotside? What do you have for cylinder pressure? Also "the base timing is at 15*"...what is your total before you start taking out for boost?
I realize you didn't ask for someone to nit-pick your build...just a few things came to mind & thought it couldn't hurt to ask. Lorne

 

it would spool but much much slower and would only go to about 5psi max i dont know what my cylinder pressure is but it has stock dish pistons and and has not been decked i dont know how much timing the centrifugal advance adds so i have no idea what the total timing is

 

total timing is more important than base timing, might be part of the reason why it spools slow

 

it has a miss under full boost i think it might be a timing issue i am not sure i held the car at like 4000 rpm and set the timing by ear and when i put it back down at idle it was at 34 base so i am thinking that the advance might not be working so i am going to lock it out and set it at like 30* and let the ignition box pull out 1/1 ratio does that sound close

 

What's your plug gap? Could be the culprit of the miss in boost.

 

they are ngk8's with .025 gap but i drove it today after locking the dist. at 32-33 and puling out 1/1 with my box and i think it is a carb problem when the boost comes on all at once it is like it stumbles for like 2 sec and then pulls out of it just fine . it is at aroud 7 psi and creeps 1-2psi at the top i am thinking of turning it up to like 12-15 . maybe but i dont want to kill it

 

Do not turn it up until you sort out the lower boost levels first. Turning up the wick will only cause more problems and quite possibly even pop the motor. If it's stumbling once it gets into boost it's probably a lean condition. Is it backfiring through the carb or just stumbling?

 

it like a miss i think it is a head gasket the other day it pushed coolant out under boost and it is bubbling in the overflow . so i guess i will have to change that

 

Can you increase the pump shot in the carb? It seems that you have a lean spot when you suddenly go WOT. Does it pop when you roll into the throttle slowly?