[70power]

Pulling trigger on new Header Gaskets. I have narrowed it down to 3. Have 454 with 2” Headers. Square port.

All Mr Gasket
1. Cooper, .43, part # 7158 MRG
2. Aluminum, .125, part # 7408G
3. MLS, .75, part # 4816G

Suggestions?

 

[71malibuu]

Depends how the header flange looks. If it’s nice and straight with raised bead, I’d recommend aluminum.
if it’s not nice and straight or has no bead id recommend copper with a hoop.
Could also use a little sealer if needed.
MLS I’ve never used so I can’t give an opinion on that.
if the headers are off have them machine them for an oring and never look back.

 

[70power]

Depends how the header flange looks. If it’s nice and straight with raised bead, I’d recommend aluminum.
if it’s not nice and straight or has no bead id recommend copper with a hoop.
Could also use a little sealer if needed.
MLS I’ve never used so I can’t give an opinion on that.
if the headers are off have them machine them for an oring and never look back.

Thanks, look like this.

 

[shovelrick]

Ive used Mr Gasket Ultra Seal header gaskets and never had a problem as long as the mating surfaces are flat, might try some copper sealer in the tube if the surfaces of your headers arent flat and let it cure

 

[71malibuu]

Looks like You can clean the flange with a wire brush and run a soft aluminum gasket with a little sealer on the raised bead. Torque it accurately with a torque wrench and clean lubricated hardware and I’m sure it would work just fine.

 

[Kirk's67SS]

This is what I have on my BBC 454/468 from 1975 Truck Block
HEADS Edelbrock Perf RPM Alum # 6045 / 60455 Edelbrock 60455: Performer RPM 454-O Oval Port Aluminum Cylinder Head - JEGS High Performance
290cc Oval Port - Large 110cc Combustion Chambers Exhaust Port Shape Square
HEADERS Hooker # 2455-1HKR Rectangular 2” x 30” Prim Tubes / 3.5” x 10” Collector
Hooker Headers 2455-1: Competition Headers 396-502 Chevy Big Block V8 - JEGS High Performance
Remflex Header Gaskets # 2003

Never have had them leak once

 

[GoFast Beaumont]

fel pro 1412 has worked without hiccups up to 20-25psi backpressure on my ride.

 

[65cayne]

Thanks, look like this.
View attachment 743905

My last set of Hedman's had flanges that looked like that and I constantly had problems because of the raised weld around each tube. I tried several different types and believe it or not, I had the best and longest lasting luck with a red RTV and paper gasket "sandwhich" (double gasket) that I torqued and re-torqued after every cool down (most important part). Your experience may vary.

Not saying you should go with my gasket sandwich solution but I will say you should pick something that is both thick and pliable/conforming. Torque them down and RE-torque after each heat soak when the engine is dead cold. I can't emphasize that enough. Eventually, after one or eight re-torques, they will bottom out and your bolts will stay tight.

 

[mr 4 speed]

My big block Corvette has Hooker 2-1/8" primaries and I used the stock exhaust manifold gaskets. Fit perfect.

 

[Hotwire]

I would not run MLS unless the crush area of the gasket lines up w/ the raised portions of your flanges.

I'm in the ultraseal crowd and would follow GM's LS exhaust manifold torque specs. I haven't looked at my headers since I installed them, 0 leaks:

Apply a 5 mm (0.2 in) wide bead of high temperature threadlocker to the threads of the exhaust manifold bolts before installing.

• P/N 12345493 - GM High Temperature High Strength Threadlocker (U.S.)
• P/N 10953488 - GM High Temperature High Strength Threadlocker (Canada)

When tightening the exhaust manifold bolts it should be done with two passes. First tighten the two center bolts on the exhaust manifold. Then tighten the rest of the bolts, alternating from side to side, while working towards the outside bolts.

Install the exhaust manifold bolts.
Refer to the following torque sequence:
Tighten
Tighten to 10 N.m (89 lb in) on the first pass.
Tighten to 20 N.m (15 lb ft) on the final pass.

 

[70power]

I’m not against Ultra Seals. Although these are what I took off and didn’t look the best. But, when I first checked their tightness after assuming I heard an exhaust leak they were all not very tight.

 

[71malibuu]

These are what I used on a raised bead exhaust on gm iron heads. Put them on with sealer on both sides after wire brushing the header flange. I also like to put a bit of sealer on the bolts. Torque them down properly as previously stated in 2 steps. I also take the car for a drive and get it hot. Then shut it off and re-torque them. Do it again the next day cold and your good to go. The important part with using a thick soft aluminum gasket it torque and it has to be even. Otherwise your chasing it. Also when you fit them, take 10 min and trim any part that hangs into the bore, if you have gasket covering any amount of the exhaust port, it’s very likely it will leak.

 

[70power]

I placed an order for 2 sets of gaskets. The Mr Gasket 7408G thick Aluminum and the Mr Gasket 4816G MLS type. I’ll install the best looking one that matches my Header flanges. Keep the other in my parts bin if issues with the other. Decided Copper wasn’t probably my best choice with raised Header flanges.

 

[70power]

Well my MLS gasket on the drivers side is leaking. I bought some of these Mahle 95021SG, also have Mr Gasket Ultra Seal 5910’s on the way. Will decide which one to try once I get the 5910.

Has anyone tried these Mahle’s?

 

[70power]

Decided to use the Mr Gasket 5910’s. I doubled them up on drivers side. Torqued starting in middle to 20 pounds. Let get nice and hot. Will check again tomorrow.

 

[Hotwire]

As stated above, try doing 2 torque passes, first one just snug, then second one to final torque. It helps to settle everything in before you compact the sealing surface of the gasket.