I got a spare set of 305 heads that I am fully porting & polishing, I had a few questions on how I would approach polishing them.

Since the fuel mixes w/ the air @ the base of the intake before they enter the head on our tpi setups, would it be wise to fully polish the intake part of the head, I mean would it hurt atomization? or does it even matter at that point.

Also I will be using a TPIS intake, so would I have to burn a prom for the head/intake combo? I don't have acess to any prom burning stuff at the moment so would my car run witht he stock prom? I mean it's not like I'm changing the cam or something.

Thanks.

 

Do not polish the intake ports. It needs that "rough" texture so the fuel and air will mix properly.

 

Ok, what is polishable on the head then??
I thought it was pointless to polish the exaust part of the head.

 

very benificial to polish the exhaust size... will reflect heat and reduce carbon build up in the port.
No harm to polish the intake side either, especially with port injection.
http://www.cardomain.com/member_page...217306&page=22

 

Now that looks more like it

thanks.

 

anyways, what about the prom stuff, will I have to get a custom one or not.

 

polishing exhaust ports will help dissapate heat and reduce carbon buildin like mentioned..also the combustion chambers can be polished for the same reason, more beneficail to iron heads then aluminum because they dont dissappate heat as quickly as aluminum...

polishing the intake ports is a bad idea...the fuel will come out of suspension and will puddle in the chambers, NOT GOOD lol...
not only will this hurt performance and gas milege it will dig into your poscket further...having to have them ported and then them performing worse then before...(edit) if the puddling is bad enough then fuel can leak down the cylinder walls past the rings and into the oil..in which case a polished intake port and puddling fuel will be the last thing u worry about (edit)
it can be argued that with enough velocity through the ports that the fuel is moving fast enough that it doesnt run down the port walls.....yea maybe for a 1000 horse big block lol, but for your everday 400 horser you will be sorry for polishing the intake ports

as far and the intake base id say that if u have an had an AFPR then bump up the psi a little...it wont make a difference untill WOT but neither will the base really

HTH

 

thanks for the tip, I do have an AFPR and it is currently @ 49 psi WOT.

 

u should be good to go then...i read in a mag that at 52 psi an l98 performed best...so for your lb9 id say 49-50 will be great

my situation was oppisite...i had the fuel pressure i wanted i just couldnt get enough air into to lean it out...it was way rich

now i have a blown motor lol so i guess thas the least of my concers....

good luck man!