User_name

iTrader: (7)

I currently have a set of ported 317's on my car with a blower cam, my original plan was to boost it but I decided I'm going to build a new motor for the boost. So for now the car will be NA and I want to do something with the heads. From what I've read the 317's are the same as the 243's except lower compression and slightly different bowl design.

Would I want to take these heads off and have them milled, how much? Or should I just get a set of 243's and spend more money to get those ported?

Thanks

User_name

iTrader: (7)

Sorry guys just saw the other thread for this.

oiLS1

good question, a guy is selling some 317s for 150, but dont know if i should just port my 806's they are millicut already

or would 241 work better unported also thinking of swapping for partial trade$

any help would be great from the experts, thanks in advance.

Mike Morris

iTrader: (55)

Keep the 317s...

User_name

iTrader: (7)

Wait, I should keep the 317's and have them milled? Does it change the combustion change much by milling off say more than 0.0030?

JoshuaGrooms83

iTrader: (2)

im wondering about this too. i hear that the 317s are good for boost cars but then i keep hearing that before boost they are a PITA when it comes to before and bog a bit before picking up? im trying to decide where to go 243 or 317 with my boost aplication?

User_name

iTrader: (7)

I'm n/a right now and I don't have a problem with the heads. I'm just looking for more power

Sales1@Texas-speed

You can keep the 317s and mill them, but depending on the size of camshaft size you may or may not need to flycut the pistons depending how much material you decide to measure.

User_name

iTrader: (7)

Any idea on what to have them milled to? I don't want to have this work done for the gains to be very minimal. The bottom end of the motor is stock.

Cam is 232/240 .595/.608 on a 115 lsa

PREDATOR-Z

First of all you need to post up what type of boost setup you plan to do and how much psi.
You'll have PTV issues if you mill the 317s and raising compression on a boosted motor is not the right thing to do. Compression on a FI motor should not exceed 9.5 scr.
On a stock shortblock you already have the wrong cam for a boosted setup. 6* positive overlap is too much for the amount of boost a stock shortblock can take reliably.
IMO you need to re-evaluate whether you are truly going FI or stay NA and then make decisions on which setup to do. FI is different than NA and you cannot just jump from one to another without redesigning your setup. Unless you have a shitload of money and just changing entire setups do not matter to you.
You have some thinking to do.

User_name

iTrader: (7)

Ok in my original post I stated I originally was planing on boosting the car as is. But now I'm going to build a new motor when I have the funds for the FI setup I want. So this engine will be naturally aspirated. That is why I posted the question that I did. As far as the cam it is the EPP blower cam. But thanks for your input

I8UR4RD

iTrader: (16)

Cam is 232/240 .595/.608 on a 115 lsa[/QUOTE]


blower cam hell yeah!

Mill em! 799 heads may be cheaper than 243's and similar. just check around if you decide on that route.

PREDATOR-Z

User, I did not say it is not a cam good for a blower. I said that it is a bit much for the amount of boost you can throw at a stock shortblock. There is a difference. That cam will work great if you throw at it 1 BAR +.
Why? Because the overlap of that cam will bleed cylinder pressure and you'll need to compensate by adding more psi boost, which a stock shortblock cannot handle reliably.
You said you'll build another motor. Are you going to be reusing the 317s on the boosted motor? If yes, then I would advise against milling.
A combo needs to be finely balanced and just throwing parts together is not going to make an optimized setup.
To optimize your setup NA, you would be better off getting another cam with the right heads.
IMO you should sit down and plan your future boost setup on paper and see if your budget will make it possible to achieve realistically within the time frame you desire. Otherwise just rethink your NA setup and get the proper parts to optimize that one.

IllusionalTA

iTrader: (9)

i milled mine .100 and flycut my piston's.. run's great..

PREDATOR-Z

impossible, .010 yes but .100 never.

IllusionalTA

iTrader: (9)

How so? Well you can come see it, it runs.. And it's done..

PREDATOR-Z

Please enough, my ribs are collapsing

IllusionalTA

iTrader: (9)

No reason as to why u think I'm fibbing.. What do I have to Gain by lying.. My heads were milled .1000000000000000 not .010 not .000001 .10000000000 and it's running great..

PREDATOR-Z

Because Steve, if you mill 317 castings .100 you'll run into some issues:

1- Alignment of intake
2- Milling .1000 means milling 14.3cc; Now 71cc - 14.3cc = 56.7cc
This translate into having to flycut for any decent size cam and seriously damaging flow on those heads.
3- What fuel are you running?

BTW you can add 1 zillion 0 right of the digit and .1=.10=.100=.100000000000, same same.

IllusionalTA

iTrader: (9)

Thx for the math lesson , all is well, intake is aligned , just fine.. Milled that too! heads flow fine, as well.. Thanks for your concern Though..