For a Flathead exhaust what...

For a Flathead exhaust what would you lose in performance and sound if you used 2.0 vs. 1.75 pipe?

A little back ground on the motor; 284 cu., triple 97's, Red's headers going in a 51 F-1.

Your opinion please.

 

I would run 2" with a large flathead, as I do with the 286" in my '32. As for sound, it really depends more on the muffler length and style you use and the health of the engine rather than pipe size. IMO.
Bob

 

1 7/8" is what they would have used for a hot setup back in the day. Not a lot of guys have 1 7/8" dies or know where to get pipe for that size so they go with 2"
larger pipe more deep a sound you will get, smaller pipe more pop and rap. You will get more backpressure for sure with smaller pipe, but I doubt you will notice the difference unless your talking HUGE horsepower.
Run some Porter mufflers, you will be VERY happy with them. They are the best out there for the money. Don't cheap out on Smitty's.
Toss the Red's in the trash and get some cast Fentons, Reds are cheap, thin and unless you weld a flange on the ends, they will leak. I can make better headers in a half hour with my Huth bender and a pair of flanges.

 

Cliffy,
I agree with your statement on 1 7/8" exhaust pipe, and the choice of mufflers other than Smithy's. I use and recommend Brockman's because they are a great local (Indiana) company to deal with and produce a high quality muffler. I've never seen or heard Porter's, but from what I know, they are also a quality muffler.
I disagree, however, with you on two points. One, Fentons do not fit ALL flathead car and truck chassis. Two, Red's headers have been made for decades, are of high quality, and are available in many designs to properly fit every flathead car and truck. To make a statement that you can build a better header in a half an hour might be true, and IF it is, then START making them, but don't "trash" someone and his business who's been at it for a very long time, along with the many other services Red's has, and does, provide. IMO
Bob

 

I like my Red's headers and Jim their is a stand-up guy.

 

Half hour, as in 30 minutes? Uh, sure. Did I tell you about the time I hammered out a set of perfect Deuce front fenders between breakfast and lunch?

Bob

 

i had 1 3/4 on my stock flatty and that backpressure worked very well with the engine, but with 286, i would definitely go with 2 inch

 

2 Inch is working great for my 59-ab

 

I was crunching numbers, trying to figure out volumetric efficiency if I was to make a set of headers from scratch. I don't know the practical application or how efficient it would be at scavenging but I calculated 2 1/2 collector if I used 1 1/2 inch outer tubes and 1 5/8 inch inner tube. I'm thinking of making a set of headers in a ram horn shape and was just playing with numbers to see if I could get a realistic 0 backpressure.

This size assumes 100% flow from all tubes. I think it's overkill, but based on those tube sizes I don't think I will err on the side of being too restrictive. If/when I do this, I will make a tech-o-matic on it.

 

I checked out the Porter Muffler web page. You have to check out the 51" Ford pick-up on their youtube page. I don't have any idea what engine is in that truck but, it sounds amazing.

 

Just a bump so I can get more info.

 

Mine had dual 2 1/2s with glass pack cherry bombs, The power was way down and droaned like hell. I switched to 2" with hushpowers (which are a glass packed oval), love the sound and no droan...

 

I told you what I've got on the truck board, but here's more detail on my experiences fwiw.

I run Red's nickel plated headers on my 48 F1. They've been there 10 years now and not a single problem on that daily driver. They fit around the steering gearbox perfectly - no problems with excess heat.

From everything I've read, cast Fentons will require custom fitting (grinding) - they weren't made for trucks and the gearbox is in the way.

I run Smitty's but won't next time. I'm on my second pair - ends broke out of the first and current set have rusted out to the point I'm pretty much using straight pipes. Which is what I plan to do for the next go-round. If I decide to run mufflers I'll try Brockman's.

 

Alright, have all the info I need to make up my mind. So I'm going with Porter Mufflers and 2 inch pipe. I'll post a before and after piece.

 

The Merc Truck is a SBF with a 302 in it.

FYI - Jim Davis at Red's Headers & Speed Equipment is a great guy! They are our newest Dealer, sending out muffs to them tomorrow.

 

Nobody has mentioned a real important factor here. Exaust valve size! You can run any size tube you want, but your valve (and very restrictive exaust runners) will be the limiting factor. Think about.
I've also done the calucations for primary tube and collector size and came up with 1.500 to 1.625 ID primary and 2.500 collector dia.
Diavol is dead on. sq rt of pi r sqd * 3

 

They are three tubes with little to no issues with clearance and hardly any bends, it isn't rocket science. Red's don't even have flanges on the end, you have to weld your own or expand them to fit your front pipes. Maybe a half hour is a little cocky....35 minutes.

Jim may be a good guy, I never said he wasn't. He has a great, simple product. His product fits the market he is selling them for...lower dollar headers that look good. The statement that they are "high quality"?!? They are a pair of flanges with $5 worth of compression bent pipe welded to them. You can put a pipe over the end and bend them to clear without any effort, the tube is certainly not the best quality you can get. 20 gauge I am guessing, I don't think it is 16 gauge. I prefer 14 gauge tube. Maybe I have not used his best stuff, I am just going by what I have installed for customers in the last couple years. I have put on three pairs of his headers in the last two years and each needed work to fit exhaust to them. Two pairs were dinged on the exit end, right out of the box. One pair had a flange that didn't line up with the bolt holes and I had to grind the flange to get them to bolt on. One pair hit the steering box. I do really like the physical looks of them however and the powdercoated pair I used was decent.
I am not saying that they are horrible, because they are not, I am saying that I prefer cast headers or I will make my own before I would buy Red's. I own my own bender, so it is a lot easier for me to make headers. For the normal guy, Red's serve the purpose just fine. I can't give my 2 cents just because the guy who makes them is a nice guy?

 

Never heard of Porters????only been makin them since the early 50s..I had em in 1951

 

He said he never heard Porter's, not that he'd never heard of them.

 

Not the best picture angles of the exhaust system. but if I ever get it back on a lift I'll take more. Right now I'm trying to make-up my mind wither to ceramic coat or not.
Some details, everyone likes details. LOL. From the collector flange to the tips 2 inch pipe with a custom crossover and Porter mufflers.

 

I've seen the universal do-it-yourself exhaust kits from Speedway Motors or on ebay, but I've only found 2.25" or larger. Does anyone know of an exhaust kit made of 1 7/8" or 2" tubing?

 

1.75" will allow 217 hp and 2.00" is good for 289 hp. Duals of course.
Chart is in Oct issue of Popular Hot Rodding.

 

I used a set of Tatom full tube headers on my 40 with flathead and Smitty

 

i need new exhaust on my 49 F-1, have a 1952 flathead with EAB heads and center drop headers and will be 2.5 pipe, the engine has a 4" stroked mercury crank mild cam 2x2 carb. setup. question is............has anyone used thrush cherry bomb glass packs? ....input anyone on the thrush glass pack?

 

You get what you pay for, that's why I went with Porters.

 

A flathead with the right exhaust system components has a sound all it's own. I started doing exhaust in the late 70s and I could never get that sound that I remembered from the 50s-60s. I always used 2" for the performance idea. Finally a Customer came in with a 51 Merc coupe and he insisted that I use 1 3/4" tail pipes exactly like he had as a kid. I did not stock 1 3/4" but I got some and did it his way. WOW! was I surprised to get that classic flathead sound again. I had 2" on my Sport Coupe. I changed it over to 1 3/4" and it made it a new car.

If you don't care about the classic sound then the 2" is fine but a Flatty needs 1 3/4" tail pipes. It's even more critical than the mufflers that you choose. IMHO

 

Anybody else have 1.75" or 2" exhaust on their flathead? I'm almost ready to fabricate the exhaust and I wouldn't mind hearing from other guys who have those sizes. I have a what I think is a stock 8BA going into a 51 Mercury.

 

I fabbed up a manderl bent 2" system on 289 inch 8BA but it is blown. I run the ported centre dump Belond style headers with a 2.5" collector.

I love the way it sounds, esp at WOT.

Rat

 

Fenton header's through 1 3/4 inch exhaust with some 18" Brockman's reversed sound real nice!

 

I run smittys and reds headers love em both but I'm cheap