I watched a friend doing dyno testing with headers on his 850HP 30th SS. At that level, and under the conditions his engine needed to operate... 5,000-7,000+rpm, the AS&M's made better HP than the Hooker LT's. When he went to to a stronger cam and made some other changes, pushing the engine over 900HP, the Hookers made more power. I bought his AS&M's for $175, and put them on my 800HP nitrous stroker. Been using them for 3 years. I bought a set of Hooker LT's to compare on my engine, but never got around to trying them. My AS&M's do have the driver's side modified so it points straight back, allowing me to use a 3" Borla XR-1 on each collector extension, then a 3" pipe on each side back to the rear axle.

The HPC coating on the AS&M's still looks "decent" even though they have had an EGT bung welded on after they were coated. I think the AS&M's are worth the $$$.

 

Great repsonses fella's, good info. So are 02 sensors needed on a 94 LT1? What type of flange do I need to buy if I want to flange my stock cat to the y-pipe (I wont be taking it to a muffler shop) and does it meet up right? Felpro 1406's, check. Has anyone used the ORP that thunderracing sells for AS&M? Injuneer, if my car will only be cammed(224/230) to see 6200 max rpm, am I looking at the wrong headers? Thanks for all the other useful information AS&M/RK Sport owners. Keep it coming if you've got anymore comments. 95bluestreak, you have email. I am happy to see all the positive feedback about AS&M. Thanks again guys.

-Dustin-

 

You MUST keep the pre-cat O2 sensors (the only ones you have on youre 94). They are required to help the PCM set the correct A/F ratio. It's possible to run without them, in constant open loop, but that can lead to poor fuel mileage and fouled plugs if you don't have the correct tune. The AS&M's come with all the emissions connections.

I use the Mr Gasket Copper Ultra-Seal SBC D-port gaskets, and ARP header bolts.

You could argue that a 1-3/4" header is a little large for a relatively stock engine with a cam, but I personnaly wouldn't consider a 1-5/8" header for anything other than a pure stock LT1. You can "grow into" 1-3/4" headers..... but 1-5/8" headers can be a real restriction as you move up to higher power levels.

The guy that I bough my AS&M's from is now using
2" custom-made step headers, but he's also over 1,300HP......

 

Food for thought:

Steve Quinn uses custom-made 1 5/8 stepped (1 3/4) headers on his naturally aspirated 9 second stock lt1 headed camaro.

Ryan

 

Step headers offer the advantages of increased low end torque, through higher port velocities at low RPM, and increased scavanging.... something to think about. But I ran a set of the JBA 1-1/2->1-5/8 step headers, and they strangled the engine above 5,000rpm - basically a bolt-on setup with a 125HP nitrous kit. I think that's what turned me off to 1-5/8" headers.

 

Yeah, I like the AS&M headers but want to run an aftermarket K Member in the future, from what I understand it just won't work. Does anyone know what the clearance issue really is between the AS&M setup and the aftermarket K Members? I think I'm going to be stuck getting the MACs because ground clearance is also an issue.

 

Here's confirmed gains from my system:

Before: Stock exhaust except gutted cat, flowmaster muffler = 13.99@99 in summer weather, 13.632@102.32 in early march weather.

After: ASM Headers, Random Tech Cat and stainless steel 3" Cat Back system = 13.4x@104.xx in 85* 90% humidity weather, 13.095@106.83 in early march weather.

Average gain was .5 and 5 mph.

 

Those ^^ are the numbers that have me favoring the AS&M so much. Great numbers Fastbird93, a basically stock LT1 gaining .5 and 5 mph in the 1/4 with a catback and AS&M So my list of things to get are:

02 sensors (2) $ ??
Felpro 1406 gaskets or Mr Gasket $ ??
AS&M headers and y-pipe $750
Flange to use with stock cat $??
Some type of locking header bolts $??
and some wrap to protect them during instal $??
Plugs $ ??
MSD superconductors $50

Am I missing anything?

Thanks guys for all your help. All comments welcome.

-Dustin-

 

Dang, those are some sweet times for a bolt-on only LT1! I don't think I've seen any traps that are higher than that with bolt ons. (there may be some, but I'm not aware of a faster trap). Doing 106.8 mph in the 1/4, Wow. Even if it was in cool weather.

Great job.

Dan

 

i have as&m headers and i want a aftermarket k member soon.is that a fact that these headers will have clearance issues with a bmr k member?damn this blows.

 

YES. I've looked into this and the BMR and ASM combo will not work. I'm not sure about the PA unit, and aparrently BMR isn't planning to rectify the situation.

stereomandan, thanks for the compliments. It was freezing cold outside, but I'd seen 106.xx a few times prior in warmer weather too. I was pretty happy with the trap, but pretty sad about the fact that I couldn't hit a 12. it was so cold that the track wasn't hooking at all. That 13.09 was on a 2.02 short time. The only mods other than the exhaust I had were the OEM ram air setup, and the fernco intake mod. The tune I had in there wasn't helping me too much as the car was burning very rich (<200 miles per tank highway). Still pretty good IMO.

 

damn fastbird thats really ****ty news.when i pulled the motor i wanted to do a bmr k member and lower a arms bad.when i pull the motor i might sell the as&m's for a set of hooker lt's just because of that unless bmr changes their design for the as&m

 

Well, when my motor gets pulled, depending on when, I may be using custom manifolds. All depends on how long my stock bottom end holds up. Longer the better. Let's me save for a turbo setup.

 

you might have to make a longer wire for plug #8, i have the msd wires and burned #8. it was too short

 

I don't have any complaints about my RKSports. Good ground clearance etc. Plug access sucks, but on a well tuned car you shouldn't need to change plugs that often. My last set of plugs lasted 35k without trouble.

I had to do the 94-95 conversion for mine, so the install may be a bit different than yours, although my catback is for a 94-95 car too. My Y-pipe bolted onto an offroad pipe which bolted straight to the cat back. No fitment problems other than I had to modify my bracket at the offroad-pipe-to-chassis (since mine is a 97 car). Other than that is was a bolt-on affaire. I don't have any before/after number since I did the heads/cam/exhaust all at the same time.

Overall I've been very pleased with the RKSports. Their design is nearly identical to the ASM's but the quality of the welds/flanges is not as good. None of that will affect overall performance IMHO though. I've had my headers since 99 and the coating is still holding up very well.

As stated by someone earlier, you can grow into a 1-3/4 header, but if you do a heads/cam or add a good shot of nitrous later, a 1-5/8 will deff. be a restriction.

Good luck with your purchase/install.

Mike