Thirdgen89GTA

iTrader: (5)

I've got the intake converted mostly thanks to a friend. But what I've found out is that the bolts do not sit flat when they are snugged down.

In pics at John's site it looks like some of the earlier intakes used half a washer or something similar before he started spot welding the intakes.

Thirdgen89GTA

iTrader: (5)

So no-one has any advice on what might be the best solution?

89gta383

iTrader: (5)

No solution besides machining the holes for the proper angle.

Thirdgen89GTA

iTrader: (5)

I've seen other solutions than that.

firehawkslplus

Arizonia Speed and Marine & Weiand (check out Holley), make little wedge shaped spacers. If I understand the problem.

Thirdgen89GTA

iTrader: (5)

That sounds like something I'd need then.

86IROCTHD

i had a problem with the actuall bolt holes not lining up like i couldnt install half of them..... had 2 keep takin the intake off and redrilling out/slotting the holes so they would go in... once torqued no leaks....

91banditt2

iTrader: (1)

TTT

Thirdgen89GTA

iTrader: (5)

Intake is sold, so for me the issue no longer exists. I'm going with a HSR, and some other "things".

Iroc n roll

Even though you sold the intake I think you deserve an answer for future searchers. There are two things at work here.

1) You need to of course re-drill the bolt holes on the intake at the correct angle for your heads.

...and what I think the problem you're having is...

2) You cannot use the stock bolts to fasten down the LT1 intake. The picture below shows what happens when you try. Notice how far the bolt sticks up, and yes that was as far as it went. You need to get some ARP intake bolts that have a smaller diameter head. These will allow you to torque down the manifold properly.

Thirdgen89GTA

iTrader: (5)

Actually my problem was that the bolts would not sit flush when it was on the test motor. The side of the bolt closer to the manifold was touching the intake surface, but the head side of the bolt was still not flush with the intake.

Its odd, my TPI sits just fine. The test motor I was using was an 87 305 TPI car with the 083 heads. Should have had the same bolt angle as my L98.

Iroc n roll

That's exactly whats happening in the picture.

86IROCTHD

actually if u go to lt1intake.com u can see what john does inorder to change the mating surface of the intake.... it looks as if the holes were just drilled in the "right" spot... but if u look at the intake and your bolt pattern u can see that the heads bolts are at an angle and the factory ones on the lt1 intake went straight up and down... u need to get a i dont know if its like a like a bit for a drill that has a shaft but the actually cutting part is flipped.. so u can re position the hole mating angle.... i know what it looks like in my head just dont know how to describe it.... sorry...

Iroc n roll

This was the first thing I said. LT1 intakes DO NOT bolt on to earlier blocks. They need to be plugged and re-redrilled at the correct angle which will give the appearence of "slotting" in some cases, which I'm assuming he has done or else he wouldn't even be close to having it bolted down at all.

91banditt2

iTrader: (1)

I'm having a hard time finding these spacers

firehawkslplus

The part # is 90748 both Jegs and Summit have them for $59.99. Jegs has a pic so you can see what your getting i.e. bolts and little wedge shaped adaptors. Hope this helps.

John Millican

iTrader: (1)

That is WAY too expensive for 4 angled washers. Wow!

Go to McMaster Carr website and do a search for "beveled washer". You will find exactly what you need. About $3 for a pack of 5 if you go with aluminum. You can get them in any material you want.

http://www.mcmaster.com/

firehawkslplus

I agree. That's why I went ahead and posted the price and checked Jegs & Summit both.

I made set for an old friend well like most things Bill and I do it's hard to tell who did what or how much.

Drop the bolt in the offending hole measure the gap on the open side. Now from that vertical line take the tape measure across to the outside (toward the cylinder head matting suface) holding the tape flush up under the head of the bolt. Then just transfer those measurements to paper and fill in the 3rd leg of the triangle, I used tape. Cut it out, put the tape on an old piece of scrap cut it ,ground it, sanded it and drilled the holes repeat..
It sounded easy and was by the 6th time eyeball engineering doesn't always go as planned.

91banditt2

iTrader: (1)

now if we could get someone to measure this gap using a OEM bolt we could have info for futur searchers.

firehawkslplus

Always seem to be behind on my skill sets. Once again 1 picture is worth a 1,000 words.

91banditt2

iTrader: (1)

some body? any body?

BigWhiteGTP

So what caused this problem? Was it a '87 and older head but the intake was for '88+ heads? Or was it that he used tpi bolts that are a tad bit taller than needed on an LT1 intake?

Now would redrilling the LT1 intake (already drilled for older head) to fit on 88+ heads be ok, by simply enlarging the holes? Or would it cause leaks?

Iroc n roll

Problem: You can't use the stock bolts, the head is too wide.

Answer: Just use the ARP bolts John used to begin with. These are the bolts I used. I'm sure these are the bolts that the other maybe 100 or so people that have done this used. I really don't understand the confusion.


To answer GTP's second question:
Slotting the holes will not cause any leaks of any kind whatsoever. The bolt holes are really not that close to the ports. Make sure you use some RTV around the coolant ports (and there only!) and you'll be fine.

Chevy86 IROC-Z

iTrader: (17)

Back from hibernation. Any updates on the gap?

91banditt2

iTrader: (1)

Holy back from the dead Batman!

WildCard600

Should have waited another month and hit it on the 15th anniversary.

Iroc n roll

Who has awakened me after 15 years of slumber.

91banditt2

iTrader: (1)

It’s hella pricey for 4 bolts and washers but 🤷🏼‍♂️
Weiand PowerCharger Intake Manifold Adapter Kit Early To Late Model Chevy Small Block

91banditt2

iTrader: (1)

https://www.thirdgen.org/forums/tpi/...rs-92-tpi.html

Chevy86 IROC-Z

iTrader: (17)

I know man. Too dang expensive.

Tuned Performance

iTrader: (92)

Would these do what you want ?

https://www.ebay.com/itm/Professiona...oAAOSwondennHk

Chevy86 IROC-Z

iTrader: (17)

Definately is what I was looking for. Gonna mock up my heads to see if i have the straight or angled bolts.

mcm95403

iTrader: (1)

So, since this thread is back from the dead - anyone just going with the 4-bolt Vortec pattern instead? Seems like it would be simple to cut aluminum tube and make short uprights to run the bolts into.