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Osco or Barrs....looking for feedback

I think both are fine OEM. I replaced with original non-OEM. I have 1991 log style 454's. I'll look at the prices next year and determine if I go OEM.
 
Osco & Barr are both established and provide consistent product. I don't think you'll go wrong with either.
 
I have used both but prefer Osco's. Osco's seemed to be a little heavier and resembles the OEM (Crusader) better on my boat. The Barr's were smoother and rounded in places where the OEM was more squared.
 
Agree... either Osco or Barr would be a good choice.
Since you are replacing risers/elbows only, are you certain that either will mate to the OEM manifolds?

Would going to complete center-rise exhaust benefit you? (baring any clearance issues)

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I've had good luck with Osco. However, I don't follow all their instructions to the letter, namely "i do use RTV, VERY THINLY applied to both sides of the gaskets". My experience is that dry gaskets tend to cause more edge rusting in salt water. Ultra copper or ultra black work well. Also, I don't remove all the primer in the area of the gasket surfaces, but you do need to insure that there are no paint drips in the area. Retorque to 25 ft/lbs or so before and after the first one or two run cycles. It WILL settle and unload the bolts.
 
I use some RTV as well after having a few "mysterious" leaks. The reason OSCO says to avoid it is subtle: gobs of RTV can plug the holes in the elbow/ riser where the water enters the exhaust stream. Use it sparingly and that won't happen.

Jeff
 
Speaking of Center Rise exhaust, is anyone aware of the amount of "RISE" over the older log type manifolds? I barely have 2-3" over the tops of my Edelbrock carbs and I have not been able to measure anyone else's installation. I believe the slope downward from the end of the engine exhaust to my mufflers will be fine as they are at the water line and have a good downhill flow. I am just a bit leary of the "hump" on the highest portion of the elbow hitting the inside of the hatch covers
 
diver_dave said:
I've had good luck with Osco. However, I don't follow all their instructions to the letter, namely "i do use RTV, VERY THINLY applied to both sides of the gaskets". My experience is that dry gaskets tend to cause more edge rusting in salt water. Ultra copper or ultra black work well. Also, I don't remove all the primer in the area of the gasket surfaces, but you do need to insure that there are no paint drips in the area. Retorque to 25 ft/lbs or so before and after the first one or two run cycles. It WILL settle and unload the bolts.
Click to expand...

I also did not follow Osco's instructions. I filed all flat surfaces and then sprayed on primer. I also use a very light coat of aviation sealer to both sides of gaskets and did the re-torque after a few heating/cooling cycles.
 
RicardoMarine said:
Agree... either Osco or Barr would be a good choice.
Since you are replacing risers/elbows only, are you certain that either will mate to the OEM manifolds?

Would going to complete center-rise exhaust benefit you? (baring any clearance issues)

images


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Click to expand...


Rick,

What is the benefit, if any, of converting from the log-style manifold to the center-rise manifolds.

Erich
 
two big benefits with the center risers: 1) they weigh less than the 'logs', and 2) the have less restriction so the engine can breathe better with them.
 
One disadvantage is that, if they have a gasket leak, water goes into multiple cylinders. With a log setup, only the first cylinder gets wet.


Jeff
 
Jeff and Mark,

Thanks for the replies. I don't see the benefit as being worthwhile unless there is a real need to replace the manifolds in a closed cooling system. Another benefit may be that I may only need the manifolds and elbows, whereas with the log-style setup a riser is needed is my setup along with the extra gaskets. I wonder if the center-rise setup would be higher without any spacer/riser?

Erich
 
fastjeff said:
One disadvantage is that, if they have a gasket leak, water goes into multiple cylinders. With a log setup, only the first cylinder gets wet.
Click to expand...
Warning! Turn off your sarcasm filters and enable sarcasm!

Yes, I'd rather pull an engine for one cylinder repair, than for multiple! :D
 
Only the low cylinder gets wet if its exhaust valve is open when the engine stops spinning...and it really doesn't depend upon the exhaust manifold style but more on the specifics of the installation as well as the failure.

Erich:
You'll have to measure what you have now to see if you will need risers if you switch. In most applications, they aren't needed but a few minutes with a pulltape will give an answer with much higher confidence....crusader install drawings used to be available on their www site - sometimes they can be of assistance, too.
 
The PO had replaced the manifolds already (I don't know when or why) with another set of OSCO log-style on my 1989 454s. I purchased the boat in 2006 and replaced the risers/elbows in spring of 2007, so they have 5 years on them now and will probably get replaced again this year. So I am just wondering if there would be any cost savings or other benefits by using center-rise manifolds and elbows only rather than just the log-style risers and elbows. If a riser is needed for proper height, then it would cost more, and just for the other possible benefits, it may not be worthwhile. If the manifolds needed to be replaced, then it would make more sense.
 
You'll have to do the math to see if there's any cost savings nowadays. There was for me when I switched (to center risers) but that was a unique situation. The big benefit for our application was two-fold: 1) got to go to a 4"ID outlet & 2) got stainless elbows (sadly they are NLA).
 
Interesting that you mention the 4" ID outlet. Do all the center-rise elbows have a 4" outlet? My existing elbows are 3" with each side, port and stbd, going to one muffler that has a 4" outlet for side exhaust. Would I also have to replace the mufflers or use a 4" to 3" reducer after the elbow? More food for thought I guess.
 
The research I did when we repowered showed a 454 would run best (economy) with 4" elbows and, when Y'ed into a muffler, to use 5" ID tube to/from the muffler.

If you enlarge the elbow and then use a reducer downstream, you don't gain any benefit (except a lighter wallet?) for the engine's breathing.
 
Looks like I will stay with the original plan to replace the log-style risers and elbows. The alternative does not seem to be dollar friendly.

Thanks Mark!

Erich
 
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