Where to get 273 Head Gaskets?

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BillGrissom

BillGrissom

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I am restoring a '65 Dart 273, 2-barrel that sat for years. I will eventually need to re-ring and get a valve job. My question is where to get a gasket kit with correct head gaskets. I see many gasket kits like "Victor FS3536" that state for 273-360 engines. Many say 273 for 1966+ only. Is this due to the different intake manifold hole angle?

Using a gasket with 4"D bores on a 273 engine with 3.625"D bore and an installed thickness of 0.02", adds ~0.05 in^3 or 0.8 cc. This lowers compression ratio ~1%, which is negligible (one post claimed to 7.5). However, it adds quench area which can increase HC emissions and lower efficiency, and could cause carbon buildup. In any event, over-sized bores look dumb. Does anyone have experience using these over-size gaskets? Is there anywhere to buy correct ones?

Not an immediate concern since I decided to leave the heads on since I measure acceptable compression in 6 cylinders (140-150 psi) and tolerable in two (120, 125 psi). Some that previously tested low have gotten better over weeks from oiling and turning the crank, so maybe just stuck rings. I will re-check after driving a while. No info on history since bought from a tow yard. For now, I am just replacing the timing set and externals, including aluminum intake (redrill holes). I have a Holley Projection w/ O2 feedback for fuel and Crane Cams XR700 optical ignition, as used for years on my '65 Newport. Will post more on the restore later.
 
Like you said, they all seem to be the over 4 inch bore deal, and yeah, that gap fills with carbon rather quickly. Couldn't find ones under .039 compressed so I made my own from .020 aluminum. What a pain! But correct bore. Sounded killer too with the improved compression. I'd post the pics, but I have a feeling that I'm not permitted yet. I decided to go another route, so now they're just hanging on the wall.
I remember a place that could make custom gaskets, any bore, but they cost something like $200 a pair or more! Yikes.
 
BillGrissom said:
I am restoring a '65 Dart 273, 2-barrel that sat for years. I will eventually need to re-ring and get a valve job. My question is where to get a gasket kit with correct head gaskets. I see many gasket kits like "Victor FS3536" that state for 273-360 engines. Many say 273 for 1966+ only. Is this due to the different intake manifold hole angle?

Using a gasket with 4"D bores on a 273 engine with 3.625"D bore and an installed thickness of 0.02", adds ~0.05 in^3 or 0.8 cc. This lowers compression ratio ~1%, which is negligible (one post claimed to 7.5). However, it adds quench area which can increase HC emissions and lower efficiency, and could cause carbon buildup. In any event, over-sized bores look dumb. Does anyone have experience using these over-size gaskets? Is there anywhere to buy correct ones?

Not an immediate concern since I decided to leave the heads on since I measure acceptable compression in 6 cylinders (140-150 psi) and tolerable in two (120, 125 psi). Some that previously tested low have gotten better over weeks from oiling and turning the crank, so maybe just stuck rings. I will re-check after driving a while. No info on history since bought from a tow yard. For now, I am just replacing the timing set and externals, including aluminum intake (redrill holes). I have a Holley Projection w/ O2 feedback for fuel and Crane Cams XR700 optical ignition, as used for years on my '65 Newport. Will post more on the restore later.
Click to expand...

Felpro and victor use to make a steel shim gasket at the correct bore size. Unfortunately they stopped making that boresize back in the early 80's. I'll bet some of those Stock Eliminator racers running 273's know where there are some stashed
 
I'm in the midst of finding parts for my 273 build. I ran into the same problem.
The 273's small bore needs a small gasket. A 4 1/8" head gasket seems too be too big to keep the compression of the Hypo 273's where it should be. The heart shaped chambers of the 273 head are oddly shaped and not symmetrical
on the arc side. A 4" diameter gasket looks like it would work best but I haven't finished checkin' things out. I do have a set of 302's that I can compare with.
toolmanmike
 
I've run the 4.000 fel-pro .039 for decades and cannot tell a difference. I've run them on 273's, all Commando's, with original heads up to pocket ported and cc"d 1.88 intake "J" heads. They've all run great! I have ordered 2 sets of the 3.625 diameter fel-pro's above from Summit Racing, since finding of their existance here. I believe a small loss of compression will make almost no difference, but I'm an Engineer. I also mill head and intake sides of the heads to get the best surfaces to seal to. That's my 2 cents.
 
66fs, What fel pro number did you order from Summit? Summit has the Q521SD's
listed as a 3.625 bore size but I saw them listed in a Fel Pro catalog as having over 4" hole. I called Fel Pro tech and they said they don't make small bore Mopar gaskets and that the Q521's were over 4" bore size. toolman
 
Yes, I ordered Q521SD's. I was very excited. Such is life. There is a 2 week backorder so maybe I'll cancell if they are normal. Thanks Toolmanmike for the info. I'll keep you informed. Dan
 
I just found and bought a #260-1153 gasket set from hd_mad_dog (Mad Dog Racing and Fastengineparts) on e-Bay. It is supposed to be a Sealed Power gasket set for 273 and 318 only. I'll have to let you know which head gaskets I get. lol I needed a full set. I looked at my gaskets this afternoon and found Magnum and 85' 318 gaskets. I'll keep you posted when I get them the middle of the week. Mike
 
Update. Since original post, I bought a full gasket set on e-bay for $35. It must have predated the 318 since the label only states 273 cu in (I'll post a photo later). I thought I scored big until I measured the head gasket bores as the usual over 4"D. Perhaps 3.625"D gaskets never existed. Has anyone ever pulled an original head? Did Chrysler already design for the later 360 bore in 1965? The compression loss is very minor (see calc above). I was more concerned with issues from the thin gap (quench, carbon chunks forming, etc), but apparently no problem.
 
I've pulled many original heads. They did have small bore gaskets. In practice there is no problem using the 4.00 bore gaskets. Sometimes we go too far down the theoretical path, myself included.
 
I'm one of those guys. (obviously) LOl It's been a while since I've built an engine. I've owned 13 Mopars and this will be my first Mopar rebuild. I'm learning
more every day. It's lots of fun and a little scary at the same time. I ask a lot of questions and learn a lot as I go. I have a hard time coming up with the $$ and the time to do this drive train rebuild project. I just want to get the best results with the $'s spent and only do it once. There's a few parts that are hard to find for the HP273 build. One is pistons. Thanks to Egge for making a duplicate of the originals for knuckle heads like me that want them. Then there's the head gaskets. Someone has some old ones laying around if no-one makes them new and the proper size. (I will use the 4" ones if needed)
I have asked questions about clutches too. The 9 1/2" stocker is pretty weak. I still haven't found a HP 10" clutch that will work with the 10 1/2" bolt circle flywheel. I'm pretty bull headed and haven't stopped looking yet! LOL Clutchmasters will probably rebuild mine with stronger springs and kevlar dics material. The new dual disc set ups look interesting but I don't have $800
to spend. That's why I dig deep to find the answers. toolmanmike
 
I just found out about this thread I hope I am ok here... I just got a set from Advance Auto, like in the earlier post it is for 273-318. I have '72 318 heads on it. It is a 65 block with a 4bbl intake. Not a hot rod or anything. It seems to run just fine, what could happen?
 
It will work fine. It just might loose a bit of compression. I took 4" gaskets off my engine and didn't have any carbon build up in the void between the bore and
the fire ring of the head gasket. (Had a lot on the pistons though) Two previous owners ago, my Dart was owned by a old man that mowed lawns and hauled his rider around his small town in a trailer. All the hot rodding I did wouldn't blow the "cobs" out. LOL I hope the 273/318 gasket sets have the correct smaller port intake and exhaust gaskets in the set. Mike
 
BillGrissom said:
Update. Since original post, I bought a full gasket set on e-bay for $35. It must have predated the 318 since the label only states 273 cu in (I'll post a photo later). I thought I scored big until I measured the head gasket bores as the usual over 4"D. Perhaps 3.625"D gaskets never existed. Has anyone ever pulled an original head? Did Chrysler already design for the later 360 bore in 1965? The compression loss is very minor (see calc above). I was more concerned with issues from the thin gap (quench, carbon chunks forming, etc), but apparently no problem.
Click to expand...

Like I said earlier Felpro offered a standard bore on up to .060 over back in the day but discontinued in the early 80's.
 
toolmanmike said:
It will work fine. It just might loose a bit of compression. I took 4" gaskets off my engine and didn't have any carbon build up in the void between the bore and
the fire ring of the head gasket. (Had a lot on the pistons though) Two previous owners ago, my Dart was owned by a old man that mowed lawns and hauled his rider around his small town in a trailer. All the hot rodding I did wouldn't blow the "cobs" out. LOL I hope the 273/318 gasket sets have the correct smaller port intake and exhaust gaskets in the set. Mike
Click to expand...

Thanks Mike,
Car runs fine its a driver, when the secondaries open up it goes fast. Intake gaskets were good to go it has 318 heads with a new intake. Exhaust was good too. Thanks again.
 
toolmanmike said:
I'm one of those guys. (obviously) LOl It's been a while since I've built an engine. I've owned 13 Mopars and this will be my first Mopar rebuild. I'm learning
more every day. It's lots of fun and a little scary at the same time. I ask a lot of questions and learn a lot as I go. I have a hard time coming up with the $$ and the time to do this drive train rebuild project. I just want to get the best results with the $'s spent and only do it once. There's a few parts that are hard to find for the HP273 build. One is pistons. Thanks to Egge for making a duplicate of the originals for knuckle heads like me that want them. Then there's the head gaskets. Someone has some old ones laying around if no-one makes them new and the proper size. (I will use the 4" ones if needed)
I have asked questions about clutches too. The 9 1/2" stocker is pretty weak. I still haven't found a HP 10" clutch that will work with the 10 1/2" bolt circle flywheel. I'm pretty bull headed and haven't stopped looking yet! LOL Clutchmasters will probably rebuild mine with stronger springs and kevlar dics material. The new dual disc set ups look interesting but I don't have $800
to spend. That's why I dig deep to find the answers. toolmanmike
Click to expand...

WHY DONT YOU JUST USE A CENTER FORCE 10 1/2 ? OR ARE YOU TRYING TO KEEP THE ORIGNAL BELL HOUSING?
 
I want to keep the original bellhousing. Mike
 
A couple years ago I did my 273 and I found a company that did copper gaskets. The bore was closer than any others but they were expensive. I`ll see if I can find the receipt and pass along who it was that made them.
 
unless I missed some info, has any one checked cometic head gaskets, they can be made bore specific and thickness specific! they are a mls design. I use them on my race car!
 
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