I talked to Mike a number of years back. He was working out of a shop where he had an arrangement with the owner. He said he could improve the Gessler numbers, but it was not worth sending the heads to the other coast and back for the improvement he was talking. Cheryl
I had his price list on file and one flow report. I have a habit of saving stuff likw this when I see it online. I don't know which 'stage' the flow results are for. The valve sizes (1.915 and 1.55) with 0.322" undercut stem match what I got from TA. 150# valve springs are stiff. TA Stage 3's are 140#. It was said recently (rumored?) there is a 2 year wait for porting work.
I think the information in the last chart is from the Team Buick reference site. Each time I see it, I think that Bob's work should be added to it. He was showing so much promise before he passed on..
All, Mike has the head that Bob got 262cfm out of one intake port @6oo lift. I got ahold of this head by chance & sent it to Mike about a year ago. Testing & appearance reveled the floor of the intake was dropped pretty excessively to make this number. Mike is now sonic testing of this port to see how much metal is left to be able to copy this onto other heads. We all know the fact that there was horrible core shift in the later years & all heads can't be made the same because of this. This discussion with Mike was only 2 nights ago & he has much other work to keep himself busy as he has to pay his bills etc. For Mike this is not a HOBBY but it's his life so that concentrating on "Nail" heads is more like a hobby & not just an income maker. Then again everything takes time & I'm sure Mike will get on it to see what can be done IF it can be copied at all. Tom T.
here is one of the sets I have done. ported and stock. It looks like everyone is basely close on the stock flow numbers.
Wow, Bob sure was an artist when it came to porting, 262 cfm is huge. If he dropped the floor, I'd assume that means the short turn was lowered and laid back a lot. The pinch point is the 1-2" before the valve guide. I figure he raised the roof first. Maybe the next step is to lower the floor at the short turn to straighten out the port? I made a mold of the stock port. The short turn does a weird curve backwards as it goes around the valve. That has to be hell at higher velocities. I finished up the mods on my heads.... mostly opening the throat a little and laying the short turn back a little. Also raised the roof about 0.050" at the pinch. I've been obsessing about what i 'could' do next but I don't want to ruin anything. I'll be taking them to the shop as soon as the valve seals show up. Hoping they have a source to flow test them, would be nice to know how I did.
And a mold of the exhaust. This is after I did the blending and work around the valve guide. The short turn is a joke. I did round it off, tho it looks like the obvious fix it to lower it a good 3/16".... I have no idea if that can be safely done.
In my opinion pretty hard to ruin a set as long as you don't hit water. These things are just bad. Getting the valve job right and getting the valves unshrouded in the combustion chamber are the biggest challenges to the home porter, For the home port job can't go wrong by following the Russian kid on YouTube. I think changing to smaller valve stems is the last resort for the least gain. The backside shape can have dramatic effects on flow hard to sort out without a flow bench. Basically there's only so much that can be done with the castings as water jackets are everywhere. These engines need to seriously over cammed and high compression for max performance as a crutch I just got my solid roller from T/A 244-254 @.050 .510 lift 107 LSA. custom grind my specs. For full race should be in the 270+ @.050 range. So my solid cam is a max street effort in my opinion. I have all 3 Comp thumper grinds to try first, which get slot of hate. I think they what these sleepy engines need.
I think Walt's work is spot on for a home porter looks good. I would guess your in the 225-230 cfm if you pressed out the guides and modified the intake guide area,
The Russian kid, 'whatever' , did hit water. He tried to open up the intake bowl on the exhaust side. He did get it welded up tho. There was another guy, I think on the Hamb board that broke thru there too. He machined it out and broke thru. I don't think there is a lot of flow on that side, the port does quite a turn around the valve stem... prob better to concentrate on the other side, away from the ex valve? Odd that Buick really narrowed the throat on that 'hi-flow?' side. whatever: Hamb guy. Intake bowl on left. You can see where he machined straight down and hit the water pocket.
Thanks, I'm not that optimistic! I did replace the guides. Ex guide is cut back to the casting. Intake guide was cut back some (protrudes 0.330" for valve support) and tapered. Chamber eye brows were removed, it only increased chamber volume about 1 cc. I thought I had improved the port restrictions significantly.... until I looked at the 'after' mold and it wasn't as much of a change as I thought. I am putting slightly larger TA valves in, that should improve the bowl-seat blend...in the pic the throat looks opened up too far.
I don't try and be a hero in that area for sure, I do get aggressive on the other side at the expense of swirl to try and get some air moving. Great info by studying those cutaways
no koffel did them they were my second set. gessler did my first set. Here are the specs on the first of Bob's he did two sets for me.
A better shot of my intake. The port is 'cutter finish. Bowl was then smoothed with rolls and 40 grit. Down the intake port. I was thinking of lowering the side at the divider, but don't want to mess it up. This was gonna be a 'near stock' build that I got a little carried away with. Hope to do at least 2 more builds in the future.
Port molds are real helpful too. Gives a different perspective on what it really looks like. I'll try to get more pics posted later. A couple more cutaway shots from the Hamb board. Maybe is user name was Gart?
Bob never messed with the exhaust as much as the intake. both Bob and Koffel and most other guys will say you get twice the power from more intake flow than exhaust.
