Putting a 2200 cfm throttle body on the same chinesium intake we been dynoing with along w a set ofatch flowed 63 lb injectors, then after every ounce of hp is wrung out switching to stock 500 efi mpi then adding highly modified 500 efi pieces one at a time

Smitty .... what you using for a controller? HP would be nice ....

That's a chit ton of work for real results - super cool! I know that you've done a lot of work with the mpi manifold before but I'm curious to see where it's limitations kick in.

Using mefi since i own a bunch of it, other than manual tuning its 1/5 the price of holley

Air sucks today, observed numbers down 21 hp, corrected numbers down slightly, its not perfect. Went up 3 jets on norms modded 4150, gained 2ft lbs corrected, lost 8 hp corrected but back to back against tims carb w real close afrs still made 16 more hp and 9 ft lbs tq. Tims FA made no difference fwiw, Smitty

Just checked ign timing, was down 2 degrees since it was set a while back, reset it where i been making best overall power, repulled, found 10ft lbs of tq its been missing for a while (back to 627 w mufflers), picked up 10hp and got it back in mid 670s with todsys air corrected, retarded cam 2 degrees from where i been running it, reset timing, pulled again, lost 20hp and 17 ftlbs tq, it really likes where its supposed to be, pretty much what bob m has told me all along!

Good to know about flame arrestor !

While motor is still warm, put cam back, reset timing, made 674.4 hp corrected thru mufflers and 686 wo mufflers today , doesn't matter hp wise if its at 13.5 or 12.8, same hp, slightly better torque, no more power to be had found from cam timing, igntion timing, othrr carbs, jetting etc, its maxed w what it has. Testing speedy2/33 outlaws carb when it comes then moving on to efi, will be consulting w bob m on a cam change, will try looser lash loops too, Smitty

What's your pipe length from collector end with and without mufflers ?

header tubes are 32" long, collectors are 4"x 24" from merger to tip when running open headers, similar in length to boat tailpipes. When I run mufflers I use 4-5" connectors to a 5" 90 hooked to a 5" 90 with gibson 5" id boat mufflers, its 60" from where it goes over collector BUT goes up in size at that point, when its slipped over collectpor I slide them on 5" or so so its effective length is 55" to tip, I picked up virtually NOTHING from having them on to open headers on 560 hp 502 I dynioed last, this motor religiously picks up 10hp and ft lbs tq when I take them off, Smitty