Hey guys,

I am concerned about one of the cooling passages on the deck of my patriot performance #2150 vortec heads. To me, it doesn't look like it will line up with the cooling passage on my 1967 327 block. And there are two holes in the block deck in the vicinity that will not line up with anything on the patriot performance 2150 vortec heads. Please see the attached picture with the area of concern outlined in red.

The other passages and holes look like they will line up.

Will these heads fit this block? Are modifications needed to either the head or the block?

Thanks for your help.

 

I've been looking at pictures of head gaskets online. This one has three holes (circled). It's the Fel-Pro 1094. One hole appears to match my heads, the other two match the block. Other gaskets I saw had the two holes like on my block, but no third. And there were even other varieties.

Would this gasket make the patriot vortec heads work with the 327 block? Or is there a need to have a shop drill matching holes in the heads, etc?

Any thoughts?

Thanks.

 

Good catch!
I would tap and plug those holes in the block and then drill the block in the correct spot.

 

My thought was the same but different as 305sbc.

Basically, to leave the block alone (since it is already assembled) and use a gasket that matches those two coolant holes (like this Mr. Gasket #1130). Put that gasket on the head (which is still loose & not assembled) and mark the position of those two holes. Then have a shop drill the two extra holes in the head to match the block. And just leave the big hole in the head, which would be covered by gasket material and the deck of the block.

I am hoping to find if anyone has done this or similar before.

 

I got a response from patriot. They said the Fel-Pro 1004 gasket makes them work. See attached gasket pic. I am not yet convinced.

I asked patriot to have their engineer confirm that they intend no flow in this area. See the attached picture of the old GM camel hump head. It has three holes in this area. The big one goes to nothing on the block. And two other small holes that line up with the block cooling holes and that I am thinking about drilling in my heads.

Would really appreciate anybody's thoughts on this.

 

Patriot never responded to my follow up question. I did drill the block like 305 sbc said, but left the other holes present. Haven't run it yet. I'll let you know how it turns out.

 

Coolant will still come up to the headgasket from the holes in the block. The gasket will probably hold with no problem, but personally I'd feel better if I tapped them and sealed them with plugs. As long as the plugs are even with or lower than the deck it's fine.

Another option is to enlarge the hole in the head and connect the holes in the head gasket so they overlap and there is a larger space for coolant flow. Many racers do similar things to increase the coolant flow in that very area due to the exhaust ports being so close. Those kinds of modifications are usually only necessary for endurance racing or for certain power-adder applications where a lot of heat builds up over time.

 

personally i think you would have been better off not drilling anything as that 1094 would have allowed the coolant to flow without drilling.

 

305sbc, yes coolant will still come up from the holes I didn't plug in the block, but it will be trapped. If you look real close at the picture of the gasket, you will see that the sealing "bead" is like a perimeter fence around all three holes, the three holes are not sealed individually. The head gasket I ended up using is .015" thick compressed. There will be a volume with the area of the perimeter fence and a height of .015" that the coolant can occupy. The perimeter fence will (should) seal the entire area and the coolant won't (shouldn't) go anywhere else. Even if I had plugged those two holes coolant would still have filled that same volume coming out of the new hole I drilled because the holes aren't sealed individually, only by the perimeter around all 3.

I did think about modifying the head instead. In fact, I mentioned it earlier as what I was planning to do. But I decided to modify the block because drilling the two holes in the head would have been quite close to the edge of the combustion chambers. It seemed like an invitation to crack over time from heat cycling. The hole I drilled in the block is much farther away from the next nearest feature in the block so I am less worried about cracking.

 

yes that is what i meant that gasket would have allowed for the coolant to flow from the 2 smaller holes on the sides to the single hole on the head you are right the gasket creates a pocket around all 3 holes there for drilling was not necessary

 

SpitotRS350, that's what patriot performance told me. I disagreed with them too. The 1094 gasket would not have allowed any significant coolant to flow in this area had I not made the extra hole. The only coolant that would have been able to flow would be that coming up out of the two holes in the block into the .015" thick region between the head and block then seeping over to the single hole in the head (which does not line up with either of the two holes in the block).

To me it was obvious that seeping type flow was not the intent of GM with the 327 block or of patriot performance with their head. Look at the picture of the camel hump head above for an idea of the type of flow that GM intended.

Anyway I haven't fired it up yet. But I'll post back here in a week or 2 to let you guys know how it turns out.

 

Limiting flow area now = cross sectional area of 3/8" hole I drilled = .375^2 * 3.14/4 = approx 0.111 square inches.

Limiting flow area without the new hole = the area of the the imaginary cylinders above the two existing block holes for a height of .015" (the holes were about 1/4" diameter but I didn't actually measure) = .25 * 3.14 * .015 * 2 holes = approx 0.0236 square inches. And this neglects the fact that there is some gasket material there, so it's not really .015" free height, really it's something less.

Therefore I now have 0.111 / 0.0236 = 4.7 times more flow area. Plus I still have the original seepage flow.

 

yeah the camel hump head has the center hole just as the patriot head did it also had the other two seeming to allow for one or the other to be used depending on the block... it really shouldnt be a problem you will just have a bit more flow... i usually try not to add holes when ever possible.

 

Agree with that 100%, it was painfull to make myself drill holes in the block!


Thanks for the input everybody. The holes are already drilled and I'll let you know if it works well once I fire it up.

 

well how did they work? i am waiting with everyone else. i dont like drilling holes either especially in questionable castings - the castings are made in china.
but we will hope yours work well and with no problems.
so let us know

 

I drilled the deck of the block (that casting was made in good old US of A), using the gasket as a template to locate the center punch. It seems to have worked out ok, so far.

I have run the engine several times, but ony driven it a few - I am gearing up to do computer tuning, and the car drives poorly on the stock tune.

The engine has probably run only 2 hours so far. That said, there is no coolant in the oil and no overheating. So far so good.

Here's a pic of the new hole just above and to the right of my finger. This is with the ruber coated steel shim Felpro head gasket.