Bowl Porting J-Heads for Street?

[YO7A66]

I will be pulling my J-heads off of my 340 soon to be able to accurately figure out what compression I am currently running. While I have them off and after I figure out the cc's, I was thinking of having the bowls ported and then flowed by a local shop so that I can give those numbers to Racer Brown for my next cam.

For a street driven car, would I be wasting my money to have the heads bowl ported and flowed?

Would Jim need to know what the heads are currently flowing or would 1970 J-heads be a good enough description for him to chose my cam as far as the head information goes.

I don't plan on racing the car but I want a strong street car. I don't have allot of money in the budget but if it makes a big difference, I would want that to be a goal.

Thanks
Dave

[Chryco Psycho]

I ti worth porting the heads if done properly ,
you will have to talk to Racer Brown to see what he needs to know

[MrMopar]

If you want a good street engine, don't go hog wild with the porting. I spoke to Jim at Racer Brown and he said to keep the runners smaller and narrower to keep velocity up for better torque. If you open them up too big, then low lift flow will suffer. A good 3 angle valve job and a mild blend to 85% of the valve size will be good enough. Don't worry about the gasket match either. Keep the intake runners a little rough and don't polish them to a smooth finish like you would do to the exhausts. The exhaust porst, however could stand a little more work so they will flow better. I have done this type of porting on my 340 heads and they flowed around 212 cfm @ .450 intake and 160 cfm @ .450 exhaust. Nothing radical, good enough for the street.

[littlecampbell]

Well my heads are ready Doug...seats, retainers, ss chevy exhaust valves ...the old seats were pounded down pretty good, so am hoping that will seal things up alot better. The nice suprise was that the heads were ported, not hogged out but it looks good. Will be polishing the exhaust ports...any suggestions? Also the de-glazing went well. Now all I need is a week off to get this thing back together.......

Oh by the way...the Flames look like they are on steriods AND crystal meth

[MrMopar]

Sounds like you are doing fine. I would use a 120 grit sanding taper for the exhausts. By the way, have you bought any chicken lately? ;D Should be getting quite a deal on it.

[littlecampbell]

Havent had any fowl lately....unreal...wonder whats next???...tomatoes?........or BEER?
A buddy of mine was at the Portland swap meet and came across a set of Diamond .040 340 pistons for a $100 US....Says they were used for 2 weeks...think i'll look into it, hes also from Portland.

[MrMopar]

yes, that sounds like a deal. make sure they are not scored. I want to hear all about your 340 once its all together. E-mail me at home, you got my address.

[70Barracuda]

Hey I saw those pistons too! Jim at RB aasked how much work was done on my heads. I told him about 4 hours. He said just right for the street. SSH 44 for me. 242 @ 50. Hyd.
1.5 Ex...1.6 Int. Crane ductiles.