Been busy doing 5 different bbc builds and dynoing. Doing current test starting today on my dyno. Pair of 1998 gen6 454s. I flowed and cleaned stock keihan injectors, bored motors .030 over to 460 cu inches, modified mpi intakes by cutting down the runners, dividers and blended entrys. Did a porting cleanup, converted heads to 11/32nd valve's, going to start w a tpis twin 68 mm bored out throttle body w a spare plenum w entry ground out to match bigger throttle body, firing swap cam w similar numbers to a 500 efi from bob m, 9cc domed pistons at 8.9-1 compression. Kevko 10 qt oil pans, eagle rods, dui ignirion modules. Motors converted to mefi3 w re-pinned mefi1 harnesses and knock control modules removed (done thru ecu on mefi3). The heads flowed about 310 intake and 220 exhaust after completed @.600 lift. Will post up results later, smitty

Used afrs tuliped, inconel exh valves, in back to back flow testing on norms flow bench they were worth about 10 cfm almost everywhere.

Looking forward to the numbers.... Marine trim dyno? I'll take 518hp...

Dry dyno headers, j607 cf, i expect 500 to 520hp, will be more like 475 real world hp IF it was going in boat after this in this configuration BUT there are more mods being done as i progress!

That's pretty darn good gains for a pretty simple 454 MPI build! Can't wait to see the results!

Ron, when you take away the diff between j607 and 1349 , a little over 15 hp, dry dyno headers and no pulleys , your talking 80 to 100 hp gain. Porting iron heads sucks, was going to be minor upgrades to heads but by time i ported them, had guides redone for 11/32, surfacing, valve job, converting rocker threads to 7/16 a set of EQ heads would have been a better direction to go! These mag motors have itty, bitty cams stock, just a cam change would have been a big difference. The throttle body, intake work etc might not even make much of a difference on only 460 cu inches but hey, why not! The mods WILL help when i bolt the whipple sidemounts on though after i break these in and see how good they are NA, Smitty

After i tune this na the whipple sidemounts are going on. Theres alot of bad press about them BUT when they came out no one was really tuning them perfect AND they all ended up on motors that were needing a bigger supercharger. These 460 bbc are a good candidate for them. I tuned a hp 500efi with one on water last year and after dialing it in it really ran pretty good.

Didn't those have auxiliary injectors ?
I'm sure auxiliary injectors and intake runners starting above the plenum floor didn't help.

per Eddie youngs advice this ones getting 2 80 lb auxiliary injectors too