bmfIROC-Z

iTrader: (1)

I just took my intake ,plenum and runners off yesterday cause' i want to make them flow a little better ,now i know to grind out the egr plate behind the throttle body and smooth out the sides but i was thinking about siamesing the plenum and intake,should i do this or not?ive read alot of posts of people saying not to do this,why should i or shouldnt i do this?any help would be appreciated.thanx in advance

customblackbird

iTrader: (15)

if its stock... basically u can just do the EGR walls. u cant port stock runners bc they are way too thin, the base could use some porting, upgrade to SLP runners, then u can do alot more porting to the plenum so ur happy lol and u'll get a good bit more HP too boot. if ur sticking to the TPI setup for good, u should get SLP runners and a high flow base to start off and then port the hell outa it.

by siamesing the plenum/runners u increase the plenum area and shortening the runners= more hp/RPM capability but u lose the tuned runner which makes all the torque from the tpi that we love, the slp runners do a good job of balancing this by increasing the plenum mildly but still usuing the individual runners for torque.

how did the granelli Maf work out for u? im thinking of getting one for my HSR 383 when i put it in bc im gona need alot more air, feel any HP difference?

bmfIROC-Z

iTrader: (1)

thanks for the reply,i was thinking of just getting some tpis bigmouth gaskets and port matching them,could i do this with stock runners?if not what all could i do to the stock tpi setup to make it perform the best it can?and the maf its about $300 but i noticed a big difference in throttle response and power compared to my stock gutted maf ,i would definately recommend it ,they say it flows 40% more air than stock maf but they are not tuned for cold air induction so if you have ram air or a cai of any sort when the temp gets below 45 degrees sometimes it will throw a code 33 ,but anyway thanks again

customblackbird

iTrader: (15)

yea i kno thats why i was thinking about it, right now just from my sig im basically stock except the intake and exhaust, my 383 will be puttin out 500hp so im prob gona need it.

umm no you wont be able to open it up enough to fit those gaskets, if u did the walls would be really thin, wit the stock setup the most u could do is port the hell outa the base and do the mild porting to the plenum... u cant touch the runners. a ported stock base prob wont flow enough as an aftermarket peice like the TPIS bigmouth. and they have alot more material so even more porting can happen and u can get serious flow #'s from a ported aftermarket setup. port the plenum and if u want port the base for now... but try to pick up a set of runners used is fine and port to them. i got a set of SLP's from a vette at a car show for 150$. slps are usually 260$ and they are usually the cheapest compared to edelbrock/TPIS/AS&M. if u port the penum and base well, the runners will hold u back. the TPI setup was designed for 305's so the intake isnt horribly restrictive like it is on a 350, but a highflow base/runner combo and some porting would give u a good bit more power.

personally i wouldnt waste ur time porting the stock stuff, the plenum if uwant is ok but the base would be a waste, get the bigmouth and start from there as far as the base is concerned, of course the runners are the next restriciton. dont waste ur time porting when ur prob just gona have to do it again most likely. porting the base is gona take alot of time too like hours upon hours. it took me like 4-5hrs to port the plenum to match the slp runners.

bmfIROC-Z

iTrader: (1)

thanks i appreciate the help.