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I think price and availability is the other big thing.
I don't know anywhere that keeps track of supercharger production numbers, but Id bet the Eaton M90 is very close to if not at the top for production volume ever made. Back in the 00s and 2010s, L67s and L32s were very plentiful in junkyards. Even just grand prix alone at their peak were selling almost 150k cars a year and the GTP option was relatively popular.
That volume also tanked the price. For awhile there you'd be lucky to get $100 for a used m90 unless it was a gen 5 or was polished or ported.
I also think it helped it was in a sweet spot for engine size. With the stock pulley supporting airflow for 240 crank hp and modular pullies to support up to 400ish wheel horsepower, it was a good fit for practically any 4 or 6 cyl.
I can see that now that you put it that way. Good point.
Here’s some pictures with the heads on. It’s a little blurry. The stud closes to the front has a angled side view of how far the studs extend.
The studs look awful far out to me - especially the two on the left in the first pic. I noticed I made a mistake in a post above, I was getting thread engagement mixed up with thread protrusion. You definitely don't need anywhere near that much protruding stud- a full thread or even a few full threads is fine. Can you wind the studs in further without 'torquing' them in? I imagine with that much tape, the finger tight rule probably doesn't work - but you should be able to wind them in very lightly with an Allen key.
I took a few pictures of what worked for me that I'll post in a minute. Granted they're on the front head (as I can't get any useful angle on the rears, especially with the stb in the way), but the same depth should work for either.
Thanks you for taking the time to take pictures. I really appreciate that. I see that I have them sticking out to much. I’m thinking it may be best for me to remove the studs an remove old Teflon tap that I single wrapped five times close to the tip of each stud. I’m thinking that if I screw stud in with current Teflon wrap it will hang past an expose threads and cause a leak. I will remove and re-wrap closer to the top of thread or even the whole tread to compensate for depth.
Last edited by lilmonteZ34; 03-25-2023 at 07:45 AM.
Your manifold bolts look nice. Where did you get your bolts from for your exhaust manifold?
Now that you mention it, I'm not sure. I could've swore they were just new replacement stock bolts, but they do appear to be higher grade / quality than OEM.
They seem to have held up pretty well whatever they are. I did the L67 swap back in like 2006 along with the first set of headers / these bolts. I swapped to these TOGs in probably around 2014 and just reused same hardware. That coating has held off rust pretty good for 15 years as an exhaust fastener.
Now that you mention it, I'm not sure. I could've swore they were just new replacement stock bolts, but they do appear to be higher grade / quality than OEM.
They seem to have held up pretty well whatever they are. I did the L67 swap back in like 2006 along with the first set of headers / these bolts. I swapped to these TOGs in probably around 2014 and just reused same hardware. That coating has held off rust pretty good for 15 years as an exhaust fastener.
That’s cool they held up well.
Removed The ARP studs. I decided to use Teflon paste this time. What Teflon paste product do you all use?
Removed The ARP studs. I decided to use Teflon paste this time. What Teflon paste product do you all use?
I just used the Permatex thread sealant / ptfe stuff they sell at the local parts store. I did use the high temp stuff although I don't really have a good reason why.
The regular stuff they sell is good for up to 300F and is rated for head bolts, so Id imagine its fine also. If you get a water cooled engine over 300F, you've got bigger problems than sealing head studs anyways. But they were practically the same price, so I figured a little more headroom on temp wouldn't hurt.
I just used the Permatex thread sealant / ptfe stuff they sell at the local parts store. I did use the high temp stuff although I don't really have a good reason why.
The regular stuff they sell is good for up to 300F and is rated for head bolts, so Id imagine its fine also. If you get a water cooled engine over 300F, you've got bigger problems than sealing head studs anyways. But they were practically the same price, so I figured a little more headroom on temp wouldn't hurt.
Cool, Thanks. That’s what I’ve been using. I just switched to Teflon tape since zzp suggested it for the head studs. I’ll be sure to pick some up. This time I plan on putting more on the threads than I usually do because I would like it to hold up.
03-24-2023, 10:30 AM
