GARY C wrote: ↑Mon Jun 17, 2019 7:28 pm
I am thinking a 2" valve and a valve job would help address some of the bowl hogness. Then maybe spend a day out here grinding and flowing little bits at a time.
I agree. I know the 2.02 intake valve “fits”, but it kind of overlaps into the spark plug trough and gets really close to the chamber. I’m looking for something around 1.98”-2”...may end up having to cut a 2.02 down a bit. A 2” intake helps get the throat percentage down to 88-89% which everyone says is better.
I’m also going to get a 1.54” and 1.60” exhaust valve and try that. I thought I had some laying around but I guess I don’t any more
I see these heads refer to a Pro Comp interchange part number. Is this the new brand name for Pro Comp?
ProComp goes by the name SpeedMaster and SpeedMaster79 now. Whether that interchange number means it is the same as the SpeedMaster/ProComp head I don't know...it may just mean it is a functional replacement/interchangeable application for that ProComp number.
I wonder if that casting is from the same place doing the better SBC casting that is a copy of the Dart Pro-1??
travis wrote: ↑Mon Jun 17, 2019 7:36 pm
I was kind of bummed at the loss of lower lift flow on the intake side, but doing some reading it seems that maybe that isn’t such a bad thing, especially if using a cam with a little bit of overlap? The exhaust side gained nicely for as little work as I did. I’m wondering if taking out the rest of that lump behind the guide would help? The ports was nice and quiet at all points before and after porting. Information I have found for the stock D0OE heads shows peaks of around 183/106 for the intake and exhaust respectively, and I’m even slightly better than the GT40P and iron GT40 heads. Other info I have found says that these heads, as they are now, will easily support 360-380hp without having to go crazy on the cam timing and compression.
Thoughts?
Low lift flow is dictated by the valve job and high lift flow is more about port shape but the valve job is still paramount. Going to a larger valve makes the ssr harder to calm down and way thinner. Take some airspeed numbers, faster side ssr make a bit wider, faster roof side make a bit higher before making valve larger. Just a valve job with a good top cut is worth a nice flow improvement.
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A not so great pic of the 65 289 heads I did for D.V.' s dyno competition with 1.85" valve. About 244 cfm with 147cc intake port. These came out of a water cooled boat so I did not push my luck with the ssr because I was worried about a corrosion pocket. The chamber in this pic is not finished. Chamber shape makes a difference on flow as well more so with bigger valves.
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Carnut1 wrote: ↑Tue Jun 18, 2019 4:05 am
0809172053.jpgA not so great pic of the 65 289 heads I did for D.V.' s dyno competition with 1.85" valve. About 244 cfm with 147cc intake port. These came out of a water cooled boat so I did not push my luck with the ssr because I was worried about a corrosion pocket. The chamber in this pic is not finished. Chamber shape makes a difference on flow as well more so with bigger valves.
Hmm...looks like you took a lot more out of the inner wall and bowl area than I did.
We took some speed readings, but the conversion was “messy” since his bench doesn’t measure actual air speed. It became more of a matter of comparing manometer readings at different points.
Your valve shrouding looks just like me, so maybe it isn’t an issue at this point?
My first thought is....... are there any of the newer castings that can get to 208+ with less work?
Another thought is....... if I were starting from scratch with a head like that I’d probably try a 1.90 valve first....... see where I could get with that.
My first thought is....... are there any of the newer castings that can get to 208+ with less work?
Another thought is....... if I were starting from scratch with a head like that I’d probably try a 1.90 valve first....... see where I could get with that.
Isn't a larger valve going to present a greater risk of finding water as he tries to lay that short turn back?
My first thought is....... are there any of the newer castings that can get to 208+ with less work?
Another thought is....... if I were starting from scratch with a head like that I’d probably try a 1.90 valve first....... see where I could get with that.
You think I should try a smaller valve? Now I’m more confused than before. I thought the idea was to get the throat percentage better?
I don’t disagree that a better starting point would be better, and that may be where I ultimately go, but I’m actually enjoying learning something with these things. Even if I don’t use them it’s been educational.
One thing I learned is that I really need a Fordom grinder. The setup Gary has is way better than mine.
Another thing is that iron sucks...in so many ways
My first thought is....... are there any of the newer castings that can get to 208+ with less work?
Another thought is.......if I were starting from scratch with a head like that I’d probably try a 1.90 valve first....... see where I could get with that.
Since your heads have already been cut for 1.94’s, and bowl hogged ....... I don’t see it as an option for that set of heads. The toothpaste isn’t going back into the tube.
My gut feeling is...... and keep in mind this is coming from someone who hasn’t done any porting on any OE SBF heads in many years........there has already been more material removed from that intake port than would be necessary to achieve that level of flow........ if one were to start with a virgin head that had the proper valve seat/bowl configuration.
But...... it’s just speculation on my part at this point.
Last edited by PRH on Tue Jun 18, 2019 10:52 am, edited 1 time in total.
RevTheory wrote: ↑Tue Jun 18, 2019 10:48 am
I appears as though I stepped in it again. I was thinking a 1.9 valve was larger than he currently sat; probably based on Charlie's pic with a 1.85.
Carry on, gentlemen.
I think they are 1.94, I just remembered I have a new set of 2.02 30* seat valves, he could go bigger and get the thread locked all at once...
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Carnut1 wrote: ↑Tue Jun 18, 2019 4:05 am
0809172053.jpgA not so great pic of the 65 289 heads I did for D.V.' s dyno competition with 1.85" valve. About 244 cfm with 147cc intake port. These came out of a water cooled boat so I did not push my luck with the ssr because I was worried about a corrosion pocket. The chamber in this pic is not finished. Chamber shape makes a difference on flow as well more so with bigger valves.
Hmm...looks like you took a lot more out of the inner wall and bowl area than I did.
We took some speed readings, but the conversion was “messy” since his bench doesn’t measure actual air speed. It became more of a matter of comparing manometer readings at different points.
Your valve shrouding looks just like me, so maybe it isn’t an issue at this point?
I was thinking the SSR was near 400? I would have to see if we took notes and recalculate, it was about 4 am by then.
I see where it could be addressed I just don't know what material there is to play with.
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
GARY C wrote: ↑Tue Jun 18, 2019 12:40 pm
I was thinking the SSR was near 400? I would have to see if we took notes and recalculate, it was about 4 am by then.
I see where it could be addressed I just don't know what material there is to play with.
I don’t think we took any notes on air speed, but I think we calculated about 362 fps at the apex of the short turn on the inner wall side (about 9” iirc), and was seeing almost 30% higher on the outer wall side, which has got to be around 400 fps. Then that little cut you did there at the fastest part picked up a few cfm above .500” and made the speed pretty much even all across the apex/floor area.
