Workin On 59

I am considering changing the intake manifold gasket in my 65 327/250hp to help avoid excessive heatsoak. On hotter days with heatsoak the carb bowls are too hot (over 150 degrees f.) and hot starts are a problem. My IR gun showed about 202 degrees f. on top the thermostat housing after climbing our long (almost half a mile) steep driveway. I will pull the thermostat and check it before changing the intake gasket. At this point I have wired open the heat riser on the passenger side exhaust manifold.

Today I asked my local NAPA dealer about a Felpro intake gasket set for a 65 FI application. He showed a NAPA part #MS9617 which appeared to be the same one for most smallblocks. It did not show a blocked heat riser (crossover) passage.

He then recommended Felpro performance intake manifold gasket, NAPA #1204, which does show blocked heat riser passage. This item was not in stock but is available within about two days.

Has anyone used NAPA part # 1204? Does it have solid metal blockoff material built into the gaskets?

I believe everything mechanical in my car is stock, including the Carter WCFB carb. According to the car's temp gauge it runs just under 180 degrees f. on cool days, a little over 180 on hot days (highway driving).

Thanks, Doug

856666

Hi Doug,

I have Felpro 1204 on my L79 with Holley for the same reason. Your engine temps are the same as mine but you have to get the heat out of the carb.

It lowered my carb blow temp by over 40 degrees. No downside only up by completing this switch. No more percolation and I can sit in stop and go traffic without stalling out or rev'ing the engine.

Felpro 1204, 1205, 1206 all have blocked ports for exhaust.

http://www.summitracing.com/parts/fel-1204/applications

Also think about removing or wiring open your heat riser valve and check the oil splash shield under the manifold - make sure it is there.

I also put a 1/4 thick 4 hole fiber gasket between the intake and carb as a heat break.

There was a thread a few weeks ago on Percolation with several good suggestions - http://forums.corvetteforum.com/c1-a...d-problem.html

Phil

plaidside

I stock and sell the 1205 FelPro in my store. I like the print-o-seal around the water jackets.
Joe

rene-paul

On my 63 250 hp wcfb I built an aluminum heat shield modeled after the Mr. Gasket heat shield that is for the Holleys and AFB's. I also installed a slit rubber hose on the fuel line from fuel pump to carb. I then wrapped that with foil. I also used the Felpro 1205's.
Make sure you have the proper vented fuel tank cap and the the pickup is good. Your exhaust will sound different with the cross over blocked. I also do not latch my hood.
I did try a 1/4 " wood spacer but that did not work for me. It is the convectional heat that we are fighting.
Keep us informed.
Rene

Workin On 59

Thanks to all for your replies concerning the Felpro intake gaskets. I plan on changing to the 1204 or 1205 gasket. It sounds like the 1205 might be the best choice.

Phil, I do have my heat riser wired open. I hope I can get the significant temperature drops that you got with your modifications.

Rene, do you keep your hood unlatched for greater clearance required with the spacer you installed or is it for more airflow? I checked my hood/aircleaner clearance with plumbers putty and it appears that I have only about 1/8th inch of clearance.....so a 1/4 inch spacer would be too much on my car for my hood to close. Also Rene did the modifications you made solve all your heat related issues?

In a previous thread it was mentioned that the WCFB with the cast iron base has less of a heat transference problem than that of aluminum based carbs. With my tight hood clearance I hope that I do not need a phenolic spacer........but if I do need one I guess I'll make it really thin. My machinist nephew volunteered to mill the top of the intake down when I have it off the car to allow a thicker spacer, but I don't really want to do that unless I have to.

Thanks again for the helpful input. Doug

jimh_1962

Felpro's 1205 fit the best when it matched up to 461x heads and performer series intake.

rene-paul

The Mr. Gasket style heat shield is only 1/16 aluminum. You will have to fab up your own as there is no shield available for the wcfb. The cast base does insulate against conductive heat. We are fighting convective heat which surrounds the carb. I leave the hood unlatched to allow for air circulation. I do not have scientific data on underhood temps. The heat shield, wrapped fuel line, and the unlatched hood worked for me.
IMHO, start with a fabbed up heatshield. Look at a pic of the Mr. Gasket shield and get the proper 4 hole carb base gasket and a piece of aluminum. Form it up to and partially around the water outlet. Thin carboard and scissors will form your template. Note clearance for linkage.
Brgds,
Rene

ryan22

Do the Felpro 1204 and/or 1205 gaskets have the exhaust port blocked by metal or just gasket material ?

Shops I'm calling are having trouble finding a intake gasket set that has the exhaust ports blocked off.

Thanks-
Ryan22

MasterDave

Hmm, I just changed mine and used the Mr.Gasket. Hot rod shop says this is the only gasket that uses the metal block off any more. Dunno, but works fine.

MikeM

See post # 51.

https://www.corvetteforum.com/forums...post1589565501

SDVette

The 1204 has metal blocking plates... the 1205 only has gasket material in the cross-over section.
NAPA can usually get the 1204 in 1-2 days.

Ask me how I know this!

Frankie the Fink

I'm using the Zip part # M-3131 on both C1 and C2 cars with many miles now -- no issues.
Some have stuck metal shims over those ports but I'm just not comfortable with that...it prob works though.

Westlotorn

Go to FMECAT.com, you can enter the part number of the Fel Pro Part or most other parts Federal Mogul makes and see a picture. I believe all Fel Pro pictures are posted.
After putting in your part number click on the Fel Pro part, example, the 1204 could be your gasket or a Champion Spark Plug, click on your gasket and you can see the picture with everything in that part number that comes in the box.

If you look lower on that screen you can get specifications, important for proper port matching.

The 1204 and 1206 have metal block off plates the 1205 has a fiber block off.
I think the 1204 has stock port size and the 1206 is for larger ports but check for yourself.

Hope that helps.
Mark

PS: Napa is one source for Fel-Pro but Fel-Pro parts are available at almost every parts store or Speed Shop. Most stores have access to next day delivery if they don't carry your part, some get same day delivery.

Frankie the Fink

Nobody's mentioned it yet but if your car isn't going to be judged toss those rubber end gaskets and just use good RTV; those gaskets slip on the Chinese walls and are leak city!

Westlotorn

True and Very good advice. I don't remember the last time I assembled with the china wall gasket, silicone works great but remember it has to be built up high enough to fill the gap completely or it can leak also.
Test fit the manifold before adding the silicone so you can see how thick you need to be with the china wall silicone install.

I know many machine shops that use silicone 100% of the time on all engines assembled with the same china wall set up. Silicone works better and is easy to do.
Need to invent a faux china wall gasket that works with silicone to keep the NCRS happy

MikeM

It'd be a cold day in H... before I'd pay $37.00 just to get a couple of little pieces of tin! 'Course, nothing is too good for the Split Window Coupe, or even the other one, is there?



PS. If the block, heads and intake haven't been butchered with too much machining and the rubber end gaskets are installed correctly, they don't "leak city". They will weep a little over time. No question the silicone is better.