Hey guys I have been bothering many forum members with noob questions about the 455s. As you might know my 68 GS is a 350 twin turbo. So I would say I know a thing or two about the sbb and how to possibly get some power out of the small powerplant. I had a disassembled virgin 70' 455 laying arround for the longest and I had to keep my reputation of "doing to much" while this pandemic bores the s**t out of me. So besides building a 72 lark with LS I did my research and decided to build the Bbb. I decided for a 464 build with wiseco flat tops reconditioned rods with Arp hardware. Main arp studs. Full JW oiling mods. The machine shop is done with the short block The heads are 661 castings that I ported mild And layed down the bosses . The shop will do a radius valve job And we will be using TA stage 1 plus springs with 69' rockers and rocker girdles + shaft studs from TA. I have no plan for this engine yet. That just gives me room for a "great" swap. I had a tread going where I was suggested many different vehicles as options. As of right now I am still undecided. But I might have a chance for a 65 c10 stepwise and that would be a great project for a BBB I think.
Did you have the block sonic tested before the rebuild? If so what kind of numbers did you see, especially the #6 cylinder pin side?
Ok cool. I'm curious to see what your block was like. I've unfortunately had two blocks not check out good enough for a performance build. One is good for a stock street motor the other one is going to be turned into a table.
You do not want a radius valve job done on the Intake side of the head, Intake airflow needs to be sheered by distinct angles in the valve job as goes passed the valve and seat area and then enters the chamber to make some turbulence so to speak. Yes, a radius valve job it will show a flow gain if tested on a bench, but in a running motor there will be poorer wet flow conditions ( bigger chunks and streams of dropped out fuel ) and the less atomized fuel will not burn at the needed rate which in turn means less power and unnessary high BSFC numbers.
Thanks for the feedback. I know there is always a pro and a con with a modification or machining option. And many opinions .... A bore makes walls thinner and the block "WILL CRACK" cast pistons will melt under boost, or even in the "sun" porting the heads DIY is dangerous if you are not a pro ( i didnt know there is porting pro's) you will have less flow etc. to many to name. Fact is a Radius valve job costs me the same as a 3 or 5 angle. and the chance for gains are much higher with a radius job, that is at least my experience. Thats why i get the radius valve job. The fuel atomization also depends quit a bit on the intake and the intake flow as well as the fuel distribution. i plan on EFI So i think this is a good bang for the buck$$$ and hopefully i can get some dyno # one day once the motor is ready
For my 2c. I believe a radius valve job is beneficial for the exhaust seat but the angle 'peaks' help shear any fuel wetting out back into droplets in the air stream on the inlet. Not so important with port injection but with throttle body injection i would definitely recommend a good multi angle valve job with a minimum of five angles with a backcut on the inlet valve to mimic the first top cut above the 45 seat.
The other thing a did not mention was that the more angles you have inplace on the valve job the less freshen up valve jobs you will beable to do before new seats are needed too be installed.
Long time no update due to life and to many projects. I stabbed the custom cam from Scotty. And got the short block assembled.
Sebastian he's talking about the crank mains. If you're using studs or ARP main cap bolts you have to have the crank mains done after everything's been torqued down. Reason being is the ARP studs or bolts have a higher clamping force and will distort the crank main bores so they need to be rehoned/bored for your crank to fit properly again.
I See, Yes this has been done by the machine shop and of course meassured. they assembled it accordingly. BTW if anybody in the DFW looking for a Old school knowledge machine shop i recommend, Wayne Calvert in Denton TX,
