Installing Mr Gasket intake manifold gaskets w/heat x-over blocking plates today!
 

I got our 1965 Tripower Rochester 2bbl carbs back from the "Titan of the Tripower" Mr Dick Boneske, after having him evaluate, MODIFY, and "pretty them up".
The main reason for sending them to Boneske was to get them modified to accommodate the performance build level of our 1965 421 that resides where a 389 would be.
Iron (6)777 heads that have been hand ported by a previous owner, along with CompCams roller tipped rockers and retainers were already in place. I sent Dick the CompCams hydraulic roller cam card, and all the other build specs.
So not only am I blocking the heat crossover, I am installing Cool Carb insulators. Instead of phenolic material, they have a layer of polymer sandwiched between a very thin aluminum sheet. When I had a slight leak at the carb fuel line inlet (which I fixed temporarily with a white Permatex paste product made for the job, and actually worked well) I saw fuel BOILING out of the carb, so in South Louisiana and Mississippi, I have decided to "turn off the heat".
I have high Hope's and expectations for our "BONESKE-FIED" Tripower, because the various problems we were having idling, starting when hot, and not getting nearly the power output we should be, if Mr. Boneske's mods don't get us where we should be, a very expensive 3x2 EFI system is the only next move, and I'd rather the carbs get the job done.
Anyway, I'll post up after I get this done.

The heat from the crossover is one of three factors that will make a combustible mixture of the gas.
The other two are velocity and amounts of fuel used.
Reducing the heat need compensated by the other two meaning you´ll have rev the engine higher and feed extra gas to the intake.
This means nothing to the 1/4 mile racers, they start at 4500 rpm´s and drive only a 1/4 mile a couple of times at weekends.
For a street driven vehicle this means worse drivability, economy and performance.

Fuel dribbling/percolating up to a half hour after shut off is often a result of the fuel line too close to hot engine parts rising the fuel pressure between the fuel pump check valve and carb inlet valve. This pressure can exceed 20 psi at times and there is NO inlet valve that holds against that kind of pressure.

I cured this issue on my 1966 Tripower GTO by using an electric fuel pump w/o check valve 25+ years ago, No heat insulators, no blocked off crossover, no percolating, no problems since. Also using the revised vented throttle body gasket in the end carbs makes for easier hot starts.

FWIW.

Actually the heads have (8)777 cast into them, not (6)777
Can anyone comment on the 8777 heads?
See pictures

1965 389 GTO/ 421 H.O. #77 heads with added 7/16" studs and guide plates hopefully used with hardened push rods. No valve spring oil shields, may have positive valve guide seals installed?
Looks nice!

I appreciate the detailed answer, and I am not arguing with what you propose.
I will say that it gets REALLY HOT in South Louisiana and Mississippi, and I know the underhood temps really get up there. Also, we are adding Vintage Air AC, but I am also installing a Cold Case radiator, which uses the BEST "new design", that being less rows (2) but larger tubes 1" part# GPG 18
The paint peeling off the intake tells me how very hot the intake was getting. The cast iron really holds the heat.
Also, besides 1320 foot WOT sprints at Gulfport Dragway, the BIGGEST car related event that we do EVERY year is Cruisin the Coast in the beginning of October. Typically the weather is GREAT, meaning relatively cool, dry, and beautiful blue skies. Still, temps get into the 80s sometimes, and LOTS OF STOP AND GO TRAFFIC.
I will keep your advice in mind.
Thanks

When I had the 421 rebuilt, I had the heads machined for Viton valve stem seals and had them installed, and it already had hardened valve seats.
Thanks for the reply!

Just to give you a heads up, those block off plates will likely have holes burned in them within 500 miles of you installing them. Speaking from experience the metal is too thin to stand up to the exhaust heat. It takes stainless much thicker than those block off plates to stop the burn through for extended driving such as street use.

That is my understanding as well. If I were to attempt a solution, would adding a thin sheet of metal to the piece that comes with the Mr Gasket gaskets, maybe sticking the metal pieces together with the High Temp red silicone and then putting them in place where they normally go, with the "button" of the supplied metal piece centered in the hole of the gasket as designed work?
Or??
I don't want to fill in the heat port..yet..in case it causes more problems like Kenth suggested.

One of our longtime members Wheelspin mentioned using a thin putty knife blade as material for fashioning a stainless steel exhaust crossover block off plate.

Robust enough to not burn through yet thin enough to crush into the gasket to seal without compromising the ability of the intake to sit down and seal up correctly.

THANKS b-man! Simple, readily available, inexpensive, no real fabrication required solution!
Many thanks. I will look at that as a solution.
Intake and valley pan painted, (I figured I'd make it look nice) so I'm taking the rest of the day off.
I'll see about finishing up tomorrow, with the exception of the "F" fitting that broke today. The one on there was pretty cheesy, so Dick Boneske is sending me one out tomorrow that he has available.
Thanks again to ALL who have replied!

Having used a ceramic coating on the exhaust manifolds on couple of engine, it can really lower under hood temps.
Not only does the manifold operate cooler, it reduced heat soak into the head. And it looks great.
Something to consider.

Thanks to this forum, this "Mopar guy" learned fairly early on that the cast iron exhaust manifolds on our 421 are Ram Air 2 manifolds. According to what I have seen on Pontiac cylinder head charts, the 777 heads are for HP 389 and 421 engines in 1965, so that all makes sense, and because it has one of the "better" cast iron manifolds, I haven't insisted on headers.
I put TTi ceramic coated polished headers on my 440 6bbl even though it had "HP" iron manifolds, they didn't appear to be as performance focused as the RA2 manifolds.
Seeing the indentions where the RA2s look "segmented" into individual runners was a plus. I don't know about getting them ceramic coated, but I'll see how much that would cost.
Any suggestions as to who to use to do that?

I talked with the "TITAN of the TRIPOWER" Mr. Dick Boneske today, and he has some
⁶⁰/¹⁰⁰⁰ or .060 thick metal heat x-over block off plates he's sending me along with the new F fitting for the 2 vacuum connectors on the intake. Dick says they are thick enough not to degrade or perforate over time, and if Boneske says so, that's all I need to know.
It would have really made me angry and frustrated to have done all of the repaint and gasket replacement and heat x-over block off, along with the requirement of the Cool Carb insulators per the manufacturer that the heat x-over MUST be blocked to prevent the possibility of melting the polymer insulation of their plates, to have had the supplied metal block offs in the Mr. Gasket kit wind up failing. They should include thicker metal block off plates!!!

Intake and valley pan repainted/touched up.
Old gasket material thoroughly removed, and surfaces cleaned, using 92% isopropyl alcohol as the last cleaning agent used. Absorbs water and evaporates without leaving any residue.
I'll be using a little RED high temp RTV for assuring proper seal here and there.
I'm taking my time because of a number of factors: bad lower back makes working bent over difficult, and that sucks, because I like doing my own work. Also taking care of one of my 3 Lab mix rescues, after she had ACL surgery about 2 weeks ago. She has to be supervised, on restricted activity, so that means either in a crate w/Elizabethan collar on or on a leash and under vigilant supervision. I'm trying not to have to crate her because honestly, THIS is nice for both of us (see pic).
The other pix show the touched up/painted valley pan and intake manifold, and the CompCams springs that were installed along with the new CC hydraulic roller lifters and cam. They are double springs plus a flat wound harmonic damper.
First class parts and machine work went into this rebuild, but we haven't EVER had the return on investment that we deserve because of the stock spec Rochesters.
I believe that now that they are "BONESKE-FIED", we are really going to enjoy driving the GTO, trips to the race track will come a lot more frequently (we like running our cars on Test and Tune night) the week of Cruisin the Coast will be a LOT more enjoyable and fun, because my wife will have a great running, idling, and WOT performing engine, and I won't have to hear her SCREAMING at me about the latest carburetor problem.

Cast iron doesn't flex much... :-(
I'm running it as is since the heat x-overs are blocked off with the ⁶⁰/¹⁰⁰⁰" plates Mr Boneske sent, and sealed w/hi-temp red gasket sealer, but both heat runner-to-cylinder head flanges on the intake didn't like being "flexed" a bit by those plates. See pix. I torqued the bolts w/a torque wrench to 40# per the service manual.
Anyone make an aluminum intake w/small center carb holes like the 65 iron intake? Boneske says no, so I'd be surprised, but I figured I'd ask...

I suspect your One-of-those-days quota has been satisfied for the foreseeable future?
Sigh...

Nice. So did the "Titan of the Tripower" Mr Dick Boneske gave you some bad advice seeing his idea just cracked your intake?

Butler seems to sell a Mr Gasket set that states "steel" block off plate. https://butlerperformance.com/i-2445...tegory:1234822

Felpro offers a gasket with the block off, BUT, I believe what you wanted to do is cut down something like the putty knife blade to the same shape as the block off filler shown in the photo and then insert it into the hole. This way it would be within the gasket material rather than on top of it so when you torque down on the manifold bolts, you are torquing down on the gasket as you should and not on the combination of gasket and steel which causes the bolts to continue to pull down over the additional thickness until they bottomed out on the head and cracked. https://butlerperformance.com/i-2445...tegory:1234822

There are other ways, like filling the head with furnace cement to create a plug. Then us a gasket that has no heat crossover to begin with and create your seal. KRE has a "trim-to-fit" with no crossover passage, you would just have to use a stock gasket to match your intake passages which should not take too much trimming, or the RA IV having the crossover insert and leave it in place. Both of these would work with the furnace cement fill. http://www.krepower.com/Pontiac%20Gaskets.htm

I read in an older hot rod magazine to just pack a bunch of aluminum foil into the passage to block it. Seems cheap enough and probably might work.

I would not go and get another intake. Have yours repaired. They make a good cast iron welding rod that should do it, or brazing might even work.

The underhood temps can be a problem. Don't use any kind of hood insulation as it traps heat. You might consider an open hood scoop insert, not necessarily the ram air tub set-up. You could have 2 inserts, one open and one closed should you encounter any rain/water. Easy enough to swap them out, but the open insert will help vent underhood heat.

The heat soak is a problem when you go to restart the car after it has been shut down hot. If it sits for any length of time, the alcohol blended fuel will evaporate over time. The cure most have found is to add an electric fuel pump to supplement the factory mechanical pump for faster start ups. You also want a return fuel line going to the gas tank if you don't already have one of these. The AC cars had these. You will need the matching gas tank sending unit having the provision for the 1/4" return line. This can help.

I did some research before I bought the intake manifold gaskets, some of that research on this forum.
The Fel-Pro intake manifold gaskets were said to have port holes for RA or SD heads, and didn't come with a metal block off plate.
The Mr Gasket intake manifold gaskets port hole size is perfect for the heads I have. The Mr Gasket composite gaskets come with thin metal heat x-over plates, which even have a round "dimple" in them to locate them in the corresponding round hole in the gasket. It was HERE on this forum that I read those only last 500 miles, they burn through, yada yada. I certainly don't want to have to do this again in "500 miles", but I do wonder why Mr Gasket would do something like this to their customers, and think a 500 mile lifespan until failure would be ok??
I'm not disappointed with Dick Boneske. I was taken completely by surprise when I saw the cracks!
Seems like in retrospect that in order to successfully put block off plates in place thick enough to last the gasket material has to be cut out. I find it very strange that this process isn't commercially available from a gasket manufacturer, or the pitfalls like I've encountered not a "sticky" post or as common a warning as saying hello when someone, like I did, posts about blocking off the heat x-overs.

You could always do what Chuck Roberts did to his 1965 original Tri-Power intake, if you could not get it welded properly.

You could have a machine shop remove the cross-over completely, use steel plates to cover the exhaust cross-over openings, and have the intake aluminized so it looked like the extremely rare 1965 aluminum Tri-Power prototype intake that a Detroit Collector showed me years ago.

Chuck's 1965 GTO always got a lot of looks when people saw that intake.

Tom V.

RAM AIR II exhaust manifolds are Round Port Manifolds which will not work on "D-Port" 1965 cylinder heads.
In 1967, Pontiac came out with the first "D-port" "Ram Air" manifolds for the GTO.

So you have 1967 "Ram Air D-port Manifolds"
You have the Round Port 1st gen heads which had the so called RAM AIR II exhaust manifolds.
You had the Ram Air IV exhaust manifolds, The RA-V exhaust manifolds, and the 455 SD manifolds.
None of the Round Port GTO style manifolds will fit on a 1965 "D-Port" head.

So not sure who told you, that you have RAM AIR II exhaust manifolds on your 65 GTO with 1965 Heads.

Tom V.

Sorry to hear about your 1965 cast iron Tri-Power Intake crack issue.