65tripleblack

I'm looking at Sweet Thunder (or similar) pipes for my 1965 to replace the original GM issue pipes. Does anybody here have experience with them? Specifically looking for info on NOISE LEVEL, and power increase. SOTP is OK, but actual, chassis dyno numbers would be best. In any response, please indicate which pipes you are referring to: 2" inners, 2 1/4'" inners, or 2 1/2" inners.

Thanks in advance.

Joe

qwik-tripp

I have a set of 2 1/4 sweet thunder pipes, kinda loud. Give me a call and i'll give you a better idea I'm actually looking for a set of gm pipes.
443-309-4090.

Scott Marzahl

The problem with Sweet Thunder is they only sell the larger pipes without the head pipe. By the time you pay a shop to fab up a head pipe and weld it up, you are looking at $700 a pair.


I just Allen's Exhaust custom build me a set of 2 1/2" inner pipes, 3" outers. I have to say, the quality is top notch, no cheasy stuff from these guys and the cost was less than most vendors charge for the standard pipes.

PM me if you want anymore info.

Scott

Frankenvette 63

I am using the 2.5" Sweet Thunder inserts in my Hooker's, loud yes, but's it's personal preference. As for performance, don't think these or any other sidepipes will make allot of difference. Sure seems faster when your going through the gears and listening to the tunes these sidepipes play! I can say only great things about their service. First set came and looked like UPS used them as fence post drivers. They shipped another set same day, for next day delivery, and I din't ask for them to do so!

65tripleblack

Frank,

Can you compare the performance to stock GM pipes? Yours should be much more free flowing. If I had Hooker 4" header sidepipes on ny Corvette, then I would almost certainly have used the Spiral Turbo Baffles inserts..........much quieter, I hear, than the chambered with perforated inners, with minimal backpressure.

Joe

MasterDave

I've got the 2.5" on my sbc. IMO they are just too loud for even my deaf ears. They do flow better than stock though.

stoly

Any more info/advice on the spiral inserts in terms of noise level compared to stock side pipes? I was thinking of making up my own side pipes using inserts but do not want to get much louder than with stock side pipes. Flow should be better...
Thanks, Stoly

Viet Nam Vett

I've got the next size down from the Sweet Thunder "GNM" ( Give No Mercy) . I think those are 2 3/4 internal 3" Extrenal. Anyway... There in use with my 65 with a BB 502. The 502 is bretahing thru a set of Sanderson Shorty Block Hugger Headers into a 3" collector.

I had to have a pipe fabbed from the collector to the ST Pipes as they came as a straight assmebly due to using headers. So add that cost in as mentioned in the above post.

They are very loud thru 1st - 4th. When dropped into 5th gear..( Keisler Tranny) they will quite down some what up to 55 MPH. However.. they are LOUD..!! I use ear plugs on long trips.

Frankenvette 63

Never owned or been around factory side pipes, so I cannot compare, sorry. As for being loud, it depends on how you drive. Under normal acceleration, they are not offensive. At WOT, that's another matter, and that's the way I want it to sound, lound enough that others take notice! My Roadster has 3:08 highway gears, so in 4th at 70mph, I'm turning roughly 3,000 rpms, and the decibel level has never caused me concern. I don't listen to the radio, but that's a sacrifice I'm willing to accept. One curious note, sidepipes are louder with the top up than down, resonatates off the top I suppose. So, put the sidepipes on, leave the top down, listen to the music of the pipes, attract some attention and have lots fun. It's all about the rolling thunder!

panchop

Well I just ordered a set of Allens sidepipes to go on my new 327 I am building. I am changing over to hoged out cast iron manifolds on this engine but I wanted the better flowing 2 1/4 inch sidepipe. Anyone need a set of sidepipe headers and factory pipes?

Mike Smith

Scott -

How do they sound and perform?

Mike

Scott Marzahl

I don't know, they just arrived this past Sat and I'm in the middle of body work on my '67 right now plus I'm building an engine for my kid's '76 in the "spare" time

panchop

is the 383 built ?

Scott Marzahl

Hey Greg,
I have all the parts together but I'm trying to finish the body work and get the car in color by the end of Summer. The stress cracks that appeared recently in the new front end (after I had it in Gel Coat) really set me back. I don't want to rush the shrinkage of the material I had to add when I ground them all out.

chub

Panchop,
do you still have the headers and factory side pipes? If so, how much do you want for them? I have a 66 vert and I am looking for a set.

Chub

panchop

PMed you.

Aussie67L71

I fitted a pair of stainless 2 1/2" inner Sweet Thunder GNM pipes to my '65 327/300 6yrs ago and haven't played the radio since. And back then, they came fitted with the header pipes - bolted straight-up to the stock exhaust manifolds. Loud? Yes! Too loud? No-way! Have to admit that to my ears my 327 '65 with the GNM's sounds better than my L71 '67 with stock GM side pipes. Best Regards, Gary (Perth, Australia).

65tripleblack

Thanks for the reply Gary. Can you give any details on how the GNM compares to the stock GM in terms of VOLUME, maybe, on a scale of 1-10? Many people have said that the Sweet Thunders sound "better". Is the tone deeper or higher pitched than stock? I'm sure that the GNM's are louder at cruise, but what about at idle?

Thanks in advance.

Joe

Aussie67L71

Joe - it's a little hard to quantify exactly what the main differences are, especially in my case where my low HP 327/300 is fitted with the GNM's and my 427/435 is fitted with stock GM. On pure volume at idle, I'd say the 327 with GNM's would rate 8/10 and the 427 with stock would be 6/10. It's under acceleration/rpm where the main difference comes in - the GNM's have more of a purer "cackle" if you know what I mean? Both are good in their own way, and I'd recommend the GNM's any day. In fact, I'll probably be changing the 427 over to the GNM's in the near future. My wife hates the GNM's - so that means they must be better, ha, ha. Oh and another thing, my 327 is a coupe and the 427 is a convertible - so this makes it a little harder to compare whilst driving. Best Regards, Gary.

65tripleblack

Thanks Gary. I get the idea, but not sure what "cackle" means. Whatever it is, it sounds like a good thing. I'll probably just go for it and try the GNM's. My engine is a 327/365, and will probably sound "good" with the GNM's. The original pipes are just waaaaay too restrictive, because the engine suffocates @ 5500 RPM.
Think I'll skull a few schooners of amber fluid now, and then throw some shrimps on the barbie!

Best,
Joe