[importsmasher]

I have a 74 350 that I am putting in my son's 69 Firebird. I ran this engine 7 years ago in a demolition derby car. At that time, I put a set of 74 #46 heads on it, and I used a set of 301 head gaskets I had kicking around. The openings for the cylinders lined up nicely with the 350 block. As I recall, I had to drill one additional hole in the gasket for a coolant passage (I compared it to the original 350 gasket).

I removed the heads afterward, and now I need to re-install them. I know the issues with the Fel Pro "350" head gasket that is really the 389-455 gasket, and the difficulty in finding proper gaskets for the 350. This is a major low buck build (and once he's out of high school, the car will likely get a 400 or a 455), so I don't want to spend 80 bucks on this old stock engine for Cometic gaskets, so I am contemplating using 301 gaskets again.

I can't seem to find any mention of anyone using these gaskets on a 350. Is there a reason for this? Will there be any long-term issues? I ran this engine for a couple of hours total in the derby car with no issues.

Thanks,
Importsmasher

[Squidward]

Interesting. I always assumed that the 301 market was even smaller than the 350 market.

I've used the basic fel-pro's on a 350. Not ideal, but working.

[steve25]

Where talking at most a 1.5 CC difference here so the compression change is almost nil !
If you want to make up the difference and have a tad more power then run a long reach plug with a taper seat that is one heat range colder than normal .
You will also find that you need no more than 33 degrees total with these plugs.

[importsmasher]

Originally Posted by steve25

Where talking at most a 1.5 CC difference here so the compression change is almost nil !
If you want to make up the difference and have a tad more power then run a long reach plug with a taper seat that is one heat range colder than normal .
You will also find that you need no more than 33 degrees total with these plugs.

So are you saying it doesn't make a measurable difference if I use the standard gasket? I am not concerned about power loss due to compression differences; I have just read about quench issues and octane tolerance due to the gap between the head and block from the larger opening on the gasket. If this is not a significant concern, I may just use the standard gasket.

When you say a long reach plug (my heads are set up for a taper seat plug), can you give a part number suggestion?

Thanks,
Importsmasher

[amcmike]

Originally Posted by importsmasher

So are you saying it doesn't make a measurable difference if I use the standard gasket? I am not concerned about power loss due to compression differences; I have just read about quench issues and octane tolerance due to the gap between the head and block from the larger opening on the gasket. If this is not a significant concern, I may just use the standard gasket.

I guess that's what I was thinking too. The larger bore of the 301 dictated a larger gasket diameter. This would increase the crevice volume.

On SummitRacing you can search for Pontiac Head Gaskets by diameter. The closest, is a 3.95", which is much better than the "350" that lists at 4.12" (which does seem to be designed around a 389-428). Cometic has several in that bore size ranging from .027" to .040 compressed thickness" I'd take the heads off, measure all the piston/cylinder depths, take the worst-case minimum ,and order the gasket that gives you closest to .036" piston to head gap without going under that value. That will maximize your quench.

[Icefan71]

I bought 2 (one at a time) over the last year on ebay. There's also the gasket kit from Innovative Seal http://www.competitionproducts.com/I.../INS71884-1CS/

[importsmasher]

Bringing this back up since I'm finally getting ready to assemble the engine. Icefan71, have you actually used that set? It seems awfully inexpensive for Pontiac stuff. The picture is Chevy, but it could be a generic picture. I'm wondering if the head gaskets are "one size fits all " or specific to the 350.

Importsmasher

[tom s]

When I built my 301-383 stroker engine and used a number 15 head the 301 gasket did not match properly with the non 301 head.I ended up with the Butler 400 gasket as it matched the combustion chamber best.It was marginal on the 301 block but was close enough to work.The felpros are generic to work with either valve angle of the Pontiac heads and did not work.Tom

[Icefan71]

I did not use that set. I sold my Lemans a few months ago. But there are others here that have used them. The bore size is 3.95" so it's not the usual one size fits all.

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[importsmasher]

Originally Posted by Icefan71

I did not use that set. I sold my Lemans a few months ago. But there are others here that have used them. The bore size is 3.95" so it's not the usual one size fits all.

Sent from my XT1080 using Tapatalk

Perfect, thanks! I'm going to order that set.

Importsmasher

[JC455]

I bought a couple sets of the Innovative Seal kits- I haven't needed to put them in use, but I pulled the head gaskets to compare them to a Fel-Pro... They are definitely smaller diameter.

[dmac]

I got a set off ebay of victor 3401 for $16 plus shipping that appear to be originals. Not the 3401 VC. They have the shape for the 'notches' in the cylinder. I haven't checked them yet against the actual 350 cylinders.

[importsmasher]

Thanks everyone for the input! I ordered the innovative seal kit this morning. Sounds like it will be a better gasket than the Fel-Pro ones, even if they aren't the same as the original ones.

Importsmasher