Polish heads on my 2.7

[matty74]

Howdy Folks,

In my grand plans to rebuild my 2.7 I was wondering is it worth getting my heads polished.

This is my configuration

2.7L JE 9.8:1 pistons
GE60 Cams
40mm webers
single plug
ssi exhaust etc..

My heads are 35/35mm I may take them to 36mm.

Now this car is a street rod not for comp racing so I want some advice to if port polishing is worth doing?

What else could I do to make my machine even meaner.

(I have read Bruse Andersons Book)

cheers

matty74

[Steve@Rennsport]

Matty:

Generally speaking, polishing the ports just makes them pretty,.......there is no flow benefit unless they are enlarged and recontoured by someone who REALLY knows these heads and has extensive flow bench experience.

Leave them at 35 or 36mm depending on what venturies you will use in your carbs. If you are looking for max HP, you can open them to 38mm.

Shape is more important than finish; all things being equal.

[matty74]

Steve,

cheers for that, I'm using 34mm venturis in the carbs, btw care there any upgrades I can uitilise from PMO to make my webers perform better.

Like PMO have bearings rather than bushings, float's etc.. rather than fork out mega bucks for PMO's this time round, how could I improve the ida3c's I already have?

Cause it's street and I let my Mrs drive it on occassion (when I've had a few jars) I want it to be driveable in the 3000 - 5000 range but be able
to go to 6500 and know it's holding togther well, and not all top end like race car.

I want my cake and eat it too.

Matt

[Steve@Rennsport]

Matt:

LOL,..I think we ALL want our cake and eat it too,...

PMO's are really quite different in many respects and Weber's cannot be modified to accomodate all the improvements. Many years ago (well before PMO), I modified a pair of 40 IDA's to accept sealed ball-bearings on the shafts but that was a big job and not cost-effective to do anymore.

I would simply do your best job of setting your carbs up and enjoy them for what they are. When you have the $$$$, step up to find a pair of either good used PMO's or a new set.

34mm venturies are OK for what you want and I'd simply jet them appropriately for your local conditions. Spending the time to very precisely set float levels pays big dividends in how these run.

[matty74]

Steve,

thanks for the advice greatly appreciated.

Matt