thing about swapping blades is you need to be 100% round in matching the new blade. if not you will be letting air by. if it lets too much by the you wont be able to idle correctly as with the IAC completely shut you still will be getting air passing.

on my DOHC i spend lots of time porting it. went thru 3 diff stages of porting on it. 1st was just rounding the entrance lip. 2nd was feathering the rounded edge all the way back to the blade and port matching the exit. 3rd was making an inverted bell shape inside the inlet of the TB and then removing one half of the bar that holds the TB blade. allowing more cross sectional area at WOT and removing the extra threads from the screws. the DIA of the DOHC's tb is 64mm but with the extra area i calculated it would be equal to a 71mm if the blade bars were left intact.


one idea i would like to try is this.... i am currently running the maf off my DOHC as i bored it out to 3" and has very little restriciton. what if we cut the first half of the L67 TB off and take half the housing of the MAF and mount and mold it to fit the TB. this will solve the issue i have with the TB being like 80 feet long!! my DOHC's TB was less then half the size of the 3800 tb's.

my $.02 on the northstar's are they dont have a good shape to them. i would rather have a slightly smaller TB blade but have a smoother transition to increase velocity then have a bigger blade that doesnt have a good flow to the blade.

whats the diff... north star is 75mm and stock l67 is 69mm? lets find out...

Area of northstar= Pi r^2= Pi (75/2)^2= 4418mm^2 factor in some sig fig's and we have an aproximate area of 4400mm^2
Area of L67 TB = Pi r^2= Pi (69/2)^2= 3739mm^2 factor in some sig fig's and we have an aproximate area of 3700mm^2
Area if we remove 1/2 TB bar = 3*69= 207mm^2 factor in some sig fig's and we have an aproximate area of 200mm^2

so a north star has an area of 4400mm^2 and if we remove 1/2 the TB bar it will be 3900mm^2
basicly the N* has 11% more cross sectional area then if the l67's blade was removed... now does that 11% make up for the loss in velocity due to the shape? i dont see a port job on a TB making 10% more power, but 10-11% more flow?? when porting my DOHC tb i remember seeing close to if not more then 10% increase in MAF numbers. unrealated to this the boring out of the maf caused a 35% change in the maf table.