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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Surfdude on September 28, 2017, 12:08:56 pm

Title: Gen 1 intake manifold to Gen II block
Post by: Surfdude on September 28, 2017, 12:08:56 pm
I know there are lots with more experience than me and a few of you who also have to contend with the lovely CARB regulations here in California so..

1978 Chevy C10
Engine 350 SBC

Intake manifold with all of the state-mandated smog fittings casting number: 346249
The new block has a casting number of 10243880, 92-96 model years.

Will the two mate unmodified?  I ask because as I am trying to put the manifold on but the 4 center bolts look as if they are drilled at a more perpendicular (straight up) angle than the rest.  I am asking before I get the grinder out and modify the holes then epoxy back to size. 

I would like to put an aftermarket intake manifold on, but there are no intake manifolds with the magic EO (executive order) paperwork available.  Has anyone put on a Performer manifold with the EGR option and successfully passed smog in CA?

I want to keep it carb'ed  (I luvs me the sound of 2ndaries opening up) so am leaning against TBI, that and the hassle of the state come smog time. 

I appreciate all of the help, I would post pictures if I was doing anything interesting but all of us have seen greasy engines that have sat for 30+ years. 

Thanks for the help,
Title: Re: Gen 1 intake manifold to Gen II block
Post by: VileZambonie on September 28, 2017, 06:44:25 pm
It's not the block it's the cylinder heads that you have to worry about. If you are putting an early manifold on center bolt heads then you need to elongate the 4 center bolt holes. I'm fairly certain professional products intakes come with the adapters and elongated holes.
Title: Re: Gen 1 intake manifold to Gen II block
Post by: Rattler12 on September 29, 2017, 08:35:55 am
It's not the block it's the cylinder heads that you have to worry about. If you are putting an early manifold on center bolt heads then you need to elongate the 4 center bolt holes. I'm fairly certain professional products intakes come with the adapters and elongated holes.

They do. I have one on an 87 350 in my 37
Title: Re: Gen 1 intake manifold to Gen II block
Post by: Surfdude on September 29, 2017, 07:06:34 pm
Thanks, I have not contacted Professional Products.  Let's see if they have a CARB-certified intake manifold. ( I think this is a unicorn)
This is what I get for 'knowing' without verifying.  I just knew the cutoff for smog was the model year when they went to TBI when I bought this. ::)  Bah.
Well, Just have to get on with it.   Worse case I will tap the existing holes in the manifold, fill with a low grade bolt, and re-drill at a more correct angle. 
I think I can figure out something for a boss for the bolt side and braze it on afterwards. 

If only I 'knew' (there is that word again) that IF I bought an aftermarket manifold with an EGR that all would be OK with the smog police.  I personally don't see why not but  I ran into a similar situation a few years back with a cracked intake manifold and the referee would not budge.  OEM, junk it, or TBI were my options.

 Again, thanks for the help here. If Professional Products doesn't have what I can use, I will post the ensuing photos for the collective hilarity and head-shaking of the general community.

Title: Re: Gen 1 intake manifold to Gen II block
Post by: VileZambonie on September 30, 2017, 06:26:22 am
Drilling out the 4 center bolt holes in the intake is a simple and easy solution. You can make angled bushings yourself as well.
Title: Re: Gen 1 intake manifold to Gen II block
Post by: VileZambonie on September 30, 2017, 06:28:56 am
Or buy them but it's easy enough to fab something up  http://www.jegs.com/p/Professional-Products/Professional-Products-Intake-Manifold-Bushings/2849675/10002/-1