racerseks

Well, I was so hoping to get the '86 running again today, but no luck! Got so damn close too! Had to take some stuff off again to get the runners and plenum back on. Last runner to plenum bolt going in just didn't feel right, so I loosened all the rest some more, but still wouldn't go in. On the runner to plenum bolts...Are the ones in the driver's rear corner, and passenger front corner angled? If so, what the hell for? I thought it might be to make the angle easier, but seems it's going the opposite direction...and why just those two?

Anyway...I didn't go in that much, but may have messed the threads up a little on that driver's rear one. I am thinking to tap it. Anyone know what size tap I need? Ugh...

Thanks!

gman35

Hey, I am finding the same issue on a set of edelbrock hi flow runners going into a ported base that I am installing on my 1987 L98. It appears to me it is in the large head on the stock oem bolts. I'm going to try a set of small head 12 point bolts. Gary

racerseks

Good luck...Let me know if you find out the size, so I can find a tap. Thanks...

Joe C

not sure, but it seems to me, the two bolts that come in from the inner, opposite side, or (intake) manifold side are angled slightly. why? don't know, but I'm sure it has something with the manifold's layout.

every time I've tackled this job, I run a thread tracer to clean out all threaded holes. do not use a thread cutting tap. also clean the threads on all fastening bolts. a little anti-seize, and everything finger or hand tight first. can't say or recall having any issues. can't say for sure, but it sounds to me like you have, or are experiencing issues with the bolts or threaded holes. maybe things just need a little extra cleaning.

here's a fleabay link for a handy little set I've been using for years.

http://www.ebay.com/itm/METRIC-THREA...Ol4ikQz12xHSCQ



if something doesn't feel right - STOP - drop back ten and evaluate the situation. if you have to take things apart a second time, so be it. the last thing you want to do is strip out a threaded hole in the intake or plenum. take your time, be methodical, and do not force anything!

good luck -

racerseks

Yea, it's pretty strange. They are angled in such a way that it makes it more difficult to get them in or out, as opposed to easier. I can kind of see the "reason"...I mean, I think the end of the runner mating area tapers that way...but really "why", well I don't think anyone probably knows. Doesn't seem like any purpose for it. Aesthetics? What could be appealing about a crooked bolt? Kind of reminds me of that "Oetiker" clamp on the EGR pipe...Why wouldn't they just make both ends like the intake and so people could actually service this stuff?

Everything was really good and clean, and I did use anti-seize...but I guess it went in at a bit of the wrong angle. I think I might just need to chase the threads a little. Luckily, I didn't go in all that far. Would you know the size for a tap? I read M8x1.50 somwhere. I have M8x1.25 in my set, but will get the 1.5 if I know that's definitely the right one.

I gotcha...Yea, I think I took more off today then I put on

Thanks!

Joe C

ARP has a nice set of 12 points for the small block TPI -

Joe C

off the top of my head, I think the intake/plenum bolts are M8-1.25. don't think there is a M8-1.5 thread pitch, only M8-1 and M8-1.25. M10 has 1.5, 1.25, and 1.0 thread pitch.

Joe C

been there, done that (many times)

racerseks

Well that would be great, since the set I have comes with 1.25. Is there any way for me to confirm? The set comes with dies as well, and none of my bolts will thread into the die part...is that right? Thanks again!

racerseks

Yea, they can be frustrating. Seems I never have this much trouble on any other cars I have/have had, but they're not as much fun.

slhawkins

M8-1.25 is correct. I just got my 87 running today for the first time in a few weeks, put in some new runner->plenum bolts myself. :-)

*Also, they might not thread because the die is trying to cut into them a bit. Same thing happens when you chase with a tap, that's why Joe C said to use a thread chaser and not a tap.

racerseks

Thanks for pointing that out! Sometimes, it sure pays to take a break. Dunno how I missed that, but I used a tap. went through pretty clean, and not much material removed. Guess we'll see on my second attempt...An ebay seller might make a $40 sale. I cringe thinking if it was 1986...It'd probably set me back a couple grand, LoL...