I had to do some serious grinding on lower profile center bolt valve covers to clear I'm running 1.6 full roller rockers on mine with SM exhaust I love the the CMI's!!

i think bill is having second thoughts now that this is his third set..

Some doubts. I'm sure they will work great, but it doesn't inspire confidence when something so easily observed as poorly conceived is not re-designed. It makes me wonder about other stuff that I can't see.

I'm sure I will get these attached, and everything will be OK.

The first set of E-tops I had were great. They used an adapter plate that was mounted to the head, because the header tubes actually "covered" the bolt location. The adapter plate had another set of tapped holes that the headers bolted too. I agree that these are not well engineered. They shouldn't try and mount these this way. You can see on the inner 2 tubes, the outside portions have been "bent" inward slightly to allow the bolts to be inserted. These should come standard with an adapter plate like the others did.

This is the second pair of headers they have sent me, because the first came through with brackets and riser nipples I didn't order. I'm not going to ask them to re-engineer them and make a 3rd set. I seriously doubt they would do it anyway.

If you look at the pictures, you can see how even with the tops of the bolts ground off, they are still virtually touching the tubes, and the wrench, which is already thinned down greatly, would have to be paper thin to fit between the bolt and pipe.

Hi Bill , I think you will find that SS socket head bolts will work fine . I looked in my ARP book and don't see them listed but i'm sure you can get what you need at your local fastener supplier . I hope to see that bad azz Donzi at Raystown next summer . Never hesitate to ask me for help , you have my phone # . Sam

The port side header is on. A quick look at the pictures tells the story.

Cap/Socket bolts would not work. Not even close. The diameter of the head is about the same size as the "washer" part of the 12-point, which is too big. The height of the head is too tall. They take a 5/16 allen wrench, which wouldn't clear the header.

12-point ARP Header bolt is so far from working, it is a joke. The head is too tall, and even with grinding off 30% of the upper shoulder, 3 of the 6 bolts wouldn't allow a wrench to get between the bolt and header.

Stud with bolts is even more out of the picture. The height and diameter of a nut to fit the 3/8" X 16 stud is so big you can even get it started on top of the stud, much less turn it, as it is hitting the header pipe.

Button head bolt was the only thing that was even close to working, and even then I had to grind off a side of the two center bolts to get them into the hole. Look at the clearance between the low profile button head and the header pipe. It is virtually non-existant. So much so, that even though they take a relatively small 7/32" Allen wrench, on the center two bolts, I could barely get the ball end allen wrench in/out of the head because it was hitting the header pipe.

And, I have a serious concern that I can put enough torque on the bolts using a 7/32" BALL allen wrench, as they are even weaker because they are thinned to create the ball. And if you broke off the end of the allen wrench, you would be completely screwed. In that tight space, I can't image you could ever get it out of the socket, or remove the bolt without destroying the headers.

I'm also sending this information to CMI, as I'm pretty convinced that this product shouldn't be sold in it's current configuration. It is impossible to install correctly.

At this point, until I hear from CMI, I'm not a happy customer.

I hope this embarrasses the hell out of CMI . .Maybe they expected you to glue them on . I hope they make it right Bill . How many years have these guys been in business ? Absolutely no thought went into that design .

So far, CMI's solution is to send shouldered hex head header bolts. They say the headers were designed to be used with this bolt configuration. Designed for them? Yes. Built to design? I'll let the pictures speak for themselves.

The shank of the ABUS lock is exactly 1/4" thick.

The 12-point head is 1/16 short of 3/8" tall.

The cap head is 1/32" MORE than 3/8" tall.

The button cap head is only 5/16" tall.

I don't believe these headers are built correctly. The clearance for a bolt on the outer pipes is workable. The clearance for a bolt of any kind on the inner two pipes is unusable. The water jacket pipe should have been welded onto the header pipe farther out, away from the base. Just my 2¢. But then, I'm not an engineer.

Dang Bill sorry your having the issues you are, are these made differently than the other sets you have had? I was thinking of having a set made for my 383 but watching this unfold I'm thinking my SM are more funcitional even if they don't look as purdy, I concour looks like a design flaw that is inconsistant among all the bolt holes.

The first set I had, that were smokin' hot, dry all the way to the tips, 4.5" diameter, polished with equal length runners, had an adapter plate the mounted to the heads using the standard mounting location. Those bolts were countersunk, so they did not protrude beyond the surface of the adapter plate.

The adapter plate was so drilled/tapped/threaded, with another set of holes that matched up with a more offset mounting bolt location that was away from the header pipe, to avoid the very thing I'm fighting with. It was an awesome design and worked great. I have no idea why these are not done the same way.

I didn't receive the Hex head header bolts today, probably tomorrow. If they bolts prove to be unusable, and I can't imagine how they could work, given the lack of height available, it will be time to have a real serious conversation with CMI.

I think the way they have dealt with this so far has been pretty pathetic, but I will give them one more chance to do the right thing, which would be take these back, and make me a set with adapter plates like the original used set I bought for the money I have spent on this exhaust and the spacer plates. And if they had any class, they would polish them at no extra charge for all the grief they have caused me.

Think about it. Their product is a high end, premium performance exhaust system. The economy is in the dumper, so purchases of their product has to been effected, so you would think they would do everything in their power to provide awesome customer service to anyone dropping some pretty serious coin on a "hobby" purchase.

Eric @ Teague Custom Marine has done a great job with all the purchases I have made through them, and has been very helpful trying to get this resolved. I have posted positive things about him and Teague through out this experience.

CMI also will get a lot of exposure as a result of this experience. The ball is in their court to decide what kind of exposure that will be.

I wanted none of this. And I'm trying to be very factual with the information I'm presenting, so anyone interested can see exactly what I'm talking about and draw their own conclusion.

I liked the first, used CMI exhaust I bought, and would have used it if it had fit. So based on that, I bought a new set from them. Not Eddie Marine. Not Stainless Marine, or any of the other options. So far, I'm pretty disappointed. I have now lost 6 weeks (and counting) of boating, trying to get CMI exhaust on my Special Keith Eickert built engine.

More to follow, I'm sure.

THIS IS PURE Make it right CMI ...Bill is a great guy and does NOT deserve this .