[OVERULD]

I just bought a 74 Formula 455 that is pretty much all original except for the exhaust. a PO installed headers with dual exhaust and FlowMaster 40s. and turn downs under the rear fenders instead of the original chrome tail pipes. Another PO replaced the FlowMaster 40s with Dynomax 17733s.

I want to go back with the RamAir manifolds made for D-Port heads, and then dual pipes back to the original style transverse mounted muffler and twin tail pipes with chrome tips.

Who would you recommend for best fit and close to factory original sound?

What style manifolds came on the D-port 455 - was it a log type manifold or the RamAir style?

What size down pipes would I need for the RamAir manifolds?


Thanks much!

BJ

[77 Canamman]

I love the sound and tucked in appearance from the Pypes SGF70 transverse muffler kit.

HOWEVER.................

I HATED the installation. It needed a lot of tweaking to make it fit nice. With your '74, the correct style tips clamp right on to the supplied tailpipes. My splitters used retarded little adapters.

If you decide to go this route, do your homework, and have a shop install it.

[SD455DJ]

BJ, My brother Dan just installed the complete 2.5" mandrel bent w/X-pipe transverse muffler system on his '74 RA455 Formula and only had minor fit issues and installed it himself with the car on jack-stands. He said he only had to make one cut and weld to make it fit perfectly. This is a 26,000 mile survivor car and totally original with the standard 455 exhaust logs. We personally don't see the benefit to going to the RA manifolds on a std motor that is going to stay that way. If you have other plans to go with higher (9.0 to 1 or more) compression and bigger cam, then, yes.

Dan says he got lucky and got a system that was bent almost perfectly for his car, not to mention, he has all the tools an knowhow to do it himself. If I had to do it myself, it would have taken me three times as long (haha).

Dennis

[77 Canamman]

Originally Posted by SD455DJ

Dan says he got lucky and got a system that was bent almost perfectly for his car, not to mention, he has all the tools an knowhow to do it himself.
Dennis

I have installed several exhaust systems, and my PYPES SGF70 was the WORST bar none!

I see that the '74 has the rubber axle brake hose in a different location than on my '77. That was one of the many sources of frustration on my install..

If you are not concerned with getting every single HP out of your engine, go with the Gardner exhaust...It will fit MUCH better the first time!

[SD455DJ]

77 Canamman, We've had similar battles on my old '73 TA that took a solid day and lots of cutting, welding and swearing to get it to fit right. Gardner is a good way to go, no doubt. BTW, I mistyped, the Formula has 33,000 miles on it.

Dennis

[OVERULD]

Dennis and 77 Canamman, thanks for the excellent input! Dennis, you've got to post a video sound clip of that exhaust on your brother's Formula! The engine in my car was built in 2009 and received some upgrades. Here is the receipt/invoice from the engine builder. I'm told that the compression ratio is now 10.5:1 so given that, I thought the higher flow ram air manifolds made better sense than the headers on it now. Having said that, if I'm going to have any clearance issues or fitment issues with the RARE manifolds, I need to know that going in.





BJ

[SD455DJ]

BJ, That is a sound engine rebuild for a cast rod 455. If it indeed has 10.5 to 1 compression, it would have to have small dome pistons, or smaller chamber heads, which I recall they are the originals that were cut a little. I wish they said on your receipts how much they cut and the compression ratio target....they never do that!

I think your actual compression is closer to the 9.25:1 value if the pistons are flat tops and the block was zero decked. With cam is perfect for that compression and should be a great runner. I agree that you should go the RA exhaust manifold route and you won't have any fitment or clearance issues at all. I do recommend a heat shield for the starter solenoid as the manifold dump is physically closer to the solenoid.

Dennis

[77 Canamman]

Using the RA exhaust manifold will allow you to use an exhaust system designed to fit a 1974 SD-455.

[napster]

BJ,

I recently had a 1970 TA finished using RARE oversized (2.5 inch outlet) roundport manifolds. They went on with no problems. To do away with the hot start issues we went with a Powermaster High Torque mini starter. The down pipe was a 2.5 inch system. I used the system that was on the car since it was new. Not my first choice, but it is a Flowmaster system that is mandrel bent and 2.5" diameter. It has an H-pipe. I did have the flowmaster mufflers removed. I didn't want the interior drone at 2,000rpm. The mufflers were replaced with Texas TA mufflers.

It is loud and probably not what you want. If you want to hear it here is a link.

https://www.youtube.com/watch?v=BAFVExVbLXY

Remember, this is the way it sounds without headers.

Jim

[OVERULD]

Originally Posted by SD455DJ

BJ, That is a sound engine rebuild for a cast rod 455. If it indeed has 10.5 to 1 compression, it would have to have small dome pistons, or smaller chamber heads, which I recall they are the originals that were cut a little. I wish they said on your receipts how much they cut and the compression ratio target....they never do that!

I think your actual compression is closer to the 9.25:1 value if the pistons are flat tops and the block was zero decked. With cam is perfect for that compression and should be a great runner. I agree that you should go the RA exhaust manifold route and you won't have any fitment or clearance issues at all. I do recommend a heat shield for the starter solenoid as the manifold dump is physically closer to the solenoid.

Dennis

Dennis, here is a link to the Keith Black pistons that were used. Would they provide a 10.5:1 ratio?

https://www.summitracing.com/parts/UEM-KB347-030/

And here are the specs on the Crane Cam

http://www.cranecams.com/product/car...detail&p=24169

Originally Posted by napster

BJ,

I recently had a 1970 TA finished using RARE oversized (2.5 inch outlet) roundport manifolds. They went on with no problems. To do away with the hot start issues we went with a Powermaster High Torque mini starter. The down pipe was a 2.5 inch system. I used the system that was on the car since it was new. Not my first choice, but it is a Flowmaster system that is mandrel bent and 2.5" diameter. It has an H-pipe. I did have the flowmaster mufflers removed. I didn't want the interior drone at 2,000rpm. The mufflers were replaced with Texas TA mufflers.

It is loud and probably not what you want. If you want to hear it here is a link.

https://www.youtube.com/watch?v=BAFVExVbLXY

Remember, this is the way it sounds without headers.

Jim

Thanks Jim. Eric Gardner told me to go with the 2.25" RARE manifolds if I go with their system for better sealing. I'd love to use an H or X pipe but not sure Gardner even offers that option.

BJ

[Formulajones]

Here is a shot of the SGF70 Pypes transverse system on my 70 Formula RAIII

Fitment was excellent, no issues at all. I used their downpipes off the manifolds as well.

This car is setup to run PS. I originally ran the Gardner OEM exhaust system on this car, then switched to this Pypes system. I can tell you with a ton of track passes, the exhaust swap alone without touching anything else on the car was worth a solid .4 to .45 tenths and 4 mph over the original Gardner system. That's a very significant improvement.

[SD455DJ]

BJ, I see those are domed pistons and they say 0.0cc's for the valve reliefs, or the dome cc's is the same as the relief cc's. That may net you 6 cc's to take out of the overall chamber volume and assuming your original 114 cc heads are cut .060", that should get you about 106-108 cc's. Without using the calculator, I guess your compression should be in the mid to high 9's. You need to have heads in the 95 cc range to get that high (96's, 6x4's, 7F3's, etc.).

How does it run on pump gas and do you need to run 93 octane or better? That would tell for sure. At 10.5 you would have detonation issues with normal timing curves.

Dennis

[OVERULD]

I'm running 93 Octane premium pump gas and it runs strong. No dentonation at all and has amazing torque. As an example, my kick-down switch is not connected - it's there but not connected. With the 3.73 gears I can go WOT at say, 45 MPH, and the car will pin you in the seat it pulls so hard - but never down shifts. If I manually pull it into second and go WOT at 45, it will put a silly grin on your face. If I do a slow roll from a stop light in first and then punch it - I better have a plan! From a stand still, flooring the throttle will make great gobs of white smoke and cause heads to turn for blocks....young girls gasp and grown men nod knowingly, wishing they were the guy holding the wheel...yeah, it runs pretty dang strong! Whatever the compression ratio is, it's working! Not sure why I want to change those 3.73s back to 3.08s???

BJ

[SD455DJ]

BJ, Looks like you are closer to 9.25 to 1 static compression, so no wonder it runs very well on 93 pump gas. I personally think it will run great with the 3.08's, you won't miss the 3.73's (I would only run those in a RAIII Bird or if originally equipped 70-71). It has tons of torque off-idle that it will still blow the tires away. It may not do what it did (be as violent) from a roll, but it'll still light them up with more drivability. You'll love the 21% lower cruise rpm however and will only be fractionally slower in the quarter mile.

Run the RAIII manifolds and the Pypes 2.5" mandrel bent system with the X-pipe and Race-Pro transverse muffler. That car will still run mid to low 13's.

Dennis

[OVERULD]

All, thanks for the input. Today I ordered the full Gardner system from ceramic coated manifold flanges to chrome exhaust tips, with all clamps and hangers. I went with Ames' FN390 2.25" cast ram air manifolds. I'm having them drop-shipped to Central Connecticut Coatings to be ceramic coated in cast gray. Eric Gardner was great to work with and very helpful in making sure I understood all the considerations before ordering. I was going to use the R.A.R.E. Manifolds but they only offered a 3-bolt collector on both left and right. Ames offered the 2-bolt left collector and 3-bolt collector on the right. Eric said Pontiac did that for a reason and the best fit for his system was to use the 2-bolt left and 3-bolt right. So, I'm looking forward to getting that and having that factory original sound I so fondly remember. With the cam, piston and head work done on this motor by previous owner Tom Glorioso, I think this set up will be fine based on everyone's input.

Stay tuned for the installation pictures and crank-up video. May be about three weeks or so.

BJ

[Formulabruce]

Eric has a 73-74 SD exhaust system there ( factory one) that they used to blueprint the HO and SD exhaust system they sell.
Back to front, with sealer. It should sound great and work well. Its Not the optimal in performance, but its very very nice, and zero mods. The Passenger side will hang slightly down more than the DS near the cross member , and they did that when Brand new.
Looks like your intake was angle milled to fit the new position and angle of the heads, so none of it is interchangeable with other pieces ( heads and intake) . Keep that in mind if you are wanting an aluminum intake someday, it may leak like crazy if you just put it on.
Good luck !! Grab a R/A oil filter adapter from Ames and a factory starter heat shield, and you should be fine on a hot re start.
Lift engine to install those R/A ceramic Beasts, and grab some stainless bolts and use some Never seize on them ...
Have fun!!
Stock ( Static) 8.4:1 CR 455 HO Round port with the Gardner system and tips installed to factor specs. ( not a race car, its a cruiser)
https://www.youtube.com/watch?v=Kx3hN1kTvZo

[OVERULD]

Ugh! Was hoping not to have to lift this engine to get those manifolds installed! So, if it is not possible without doing so, walk me through the best way to do it. Also, where can I source the stainless steel bolts needed. Bruce, in your PM youmentioned sealing this with some of the old Indian Head Gasket Cement - were you referring to the manifolds or the oil filter offset adaptor for the RA manifolds? Or Both?

Is Indian Head Gasket Cement the same as Permatex 20539 Indian Head Gasket Shellac?

Thanks!

BJ

[Formulabruce]

Originally Posted by OVERULD

Ugh! Was hoping not to have to lift this engine to get those manifolds installed! So, if it is not possible without doing so, walk me through the best way to do it. Also, where can I source the stainless steel bolts needed. Bruce, in your PM youmentioned sealing this with some of the old Indian Head Gasket Cement - were you referring to the manifolds or the oil filter offset adaptor for the RA manifolds? Or Both?

Is Indian Head Gasket Cement the same as Permatex 20539 Indian Head Gasket Shellac?

Thanks!

BJ

Bolts from fastenal, possibly home depot. Indian head sealer is for the oil filter adapter paper gaskets. May want to take off carb, and use a tight chain bolted to ends of heads across the intake, OR you could try to cushion a floor jack and raise it by the oil pan ..

[unruhjonny]

I may have missed it, but the only Firebird engines which came with the D-port RA manifolds were the 1970 RAIII cars.

Just an FYI.

[Formulabruce]

Originally Posted by unruhjonny

I may have missed it, but the only Firebird engines which came with the D-port RA manifolds were the 1970 RAIII cars.

Just an FYI.

True, but he is replacing headers and the R/A flow better than the stock manifolds, however the '70 455HO used non R/A manifolds as well..