My choice is AS&M but which do you recommend for me. I will eventually do heads and cam but not for a while. Do the siamesed breath alot better up top?

Bob

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350 TPI, 700R4(rebuilt), K&N's, MSD 6AL, Headers, Flowmaster, 160* stat, airfoil, MAF screens cut out. 13.88 @ 101.18 mph

 

i went with the LTR but i am already waiting a MONTH cause asm are on backorder

 

Did you get the Semi Siamesed or just the large tubes?

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350 TPI, 700R4(rebuilt), K&N's, MSD 6AL, Headers, Flowmaster, 160* stat, airfoil, MAF screens cut out. 13.88 @ 101.18 mph

 

LTR = Large Tube Runners.

But I don't think the siamesed are available anymore from AS&M (and TPIS). Neither of their catalogues list the siamesed runners anymore.

As for which one to get, the siamesed allows more top-end potential and higher HP. The LTRs give more bottom end torque. The LTRs look stock where as the siamese look "homemade" IMO. But, if you are striving for more top-end, I would go with the siamesed, especially if you plan on stroking your motor later. LTRs on a 383 make a ridiculous amount of torque at very low rpms. Great for burnouts, but launching becomes a serious problem.

 

AS&M has their Siamesed Runners listed still on their website at $475. A few people have said that they are on back order though. I would like to go with them I think!
I think there comes a point when you have to sacrifice a little low end torque for some high rpm HP!! I think its time!

Bob

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350 TPI, 700R4(rebuilt), K&N's, MSD 6AL, Headers, Flowmaster, 160* stat, airfoil, MAF screens cut out. 13.88 @ 101.18 mph

 

Bob, I will take another look. It was a couple of weeks ago that I looked both on the F-body and Corvette they didn't seem to list the siamesed runners. Maybe I missed it.

From what I've seen from tests, you really don't lose that much on the bottom end with siamesed. And if you have built your engine with good heads and cam, then there is usually plenty of "new found" torque anyways to more than compensate for the slight loss the siamesed runners cause. But then you can breathe at the top-end. I just wished they didn't look so homemade, that has always been my biggest beef with them.

 

I have SLP siamese runners ported to the max and I can tell you that there is no torque loss at all. No fiction or speculation, just facts.
Here is a tip:

GO WITH THE BIGGEST RUNNERS YOU CAN FIND!!!!!!!!!

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'88 GTA 350
Headers, catback, free mods, Xtreme energy cam, and intake pieces
13.51@104.27, but can run better as it is.

New 2100-2300 RPM converter is in. Hoping for 13.30 or better.

 

88 IROC BOB, I was able to find the siamesed runners at AS&M. They had it buried in their parts. Unfortunately, they want $475 for it (plus another $150 if you want polished).

 

I got the LTR. and they are STILL on back order. Its almost been a month and a half. They said they SHOULD be able to ship a set out at the end of this week. Good thing its winter.

 

Do you all think that just the intake and runner change will give a couple of tenths with what I have done already.
I know that ideally a cam and head swap would help alot but that has to wait for a while.

Bob

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350 TPI, 700R4(rebuilt), K&N's, MSD 6AL, Headers, Flowmaster, 160* stat, airfoil, MAF screens cut out. 13.88 @ 101.18 mph

 

FWIW
LTR = long (not large) tube runner

 

Go look on the www.azspeed-marine.com its Large Tube Runners

 

It is LARGE tube runner. They are the same length as the stock runners, but have a LARGER diameter, hence the name.

 

I talked to AS&M yesterday and the guy told me that they have the Semi-runners in stock ad ready to ship.

Could this be true??

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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTB, ported plenum, 52 TB, MSD 6AL, TPIS level V prom, Mod .MAF, Superior shift-kit and some minor mods. and more to come!
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)

 

They FINALLY got a shipment in. i got an email notice yesterday. Thank God.

 

LTR (long tube runner) refers to the TPI type on the L98 and whatever the 305 is. If AS&M wants to call their runners LTR (large tube runners) that's fine with me and I stand corrected.

 

And back to the question at hand, will this swap give me the .3 tenths in the 1/4 that I'm looking for????

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350 TPI, 700R4(rebuilt), K&N's, MSD 6AL, Headers, Flowmaster, 160* stat, airfoil, MAF screens cut out. 13.88 @ 101.18 mph

 

Accel large tube runners (LTR) gave my otherwise stock L98 a .3 (tenths) reduction in ET at a 2900' elevation track.

See May'99 Car Craft for further details.


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FORMULA 350 TK
Southern California 3rd Generation F-Body OrganizationŠ