[32ponchoWest]

Hello everyone! Thanks for having me here.

I have a 1932 Pontiac Sport Coupe. My build plans include installing a 1958 Pontiac 370 with a NOS Hilborn injection unit I ran across. I also plan on having the Hilborn professionally converted to EFI to make at streetable.

When mocking-up the Hilborn 347-P-8 (built for the 1957 Pontiac 347) injection to the 370, I ran into a couple of issues:

a) The upper two holes in the Hilborn flanges don't align with the holes in the head. The head casting is 528511 which confirms it's a 1958 unit.

b) The water jackets overlap by only 1/3 at best.

I was told there are some folks here that have extensive experience with the older Hilborn injection units, and I was hoping maybe they could shed some light upon my dilemma.

I attached some photos that will hopefully help.

Thank you!

[Jack Gifford]

The injectors are apparently for later than 1960 heads.
You might want to consider using later heads on the '58.

[lrust]

@32ponchowest, I have the same Hilborn 347-P-8 unit and I am considering options on how to use it. Can you share how you are going to convert to modern EFI? Thanks.

[Bill Hanlon]

You sure it is not a 347-P-8-A which is for later Pontiac heads?

[tom s]

347 should match 55-58 water pattern?Tom

[32ponchoWest]

Originally Posted by Bill Hanlon

You sure it is not a 347-P-8-A which is for later Pontiac heads?

I just double-checked. The casting number is definitely 347-P-8

The heads are definitely 528511 which confirms a 1958 370.

The Hilborn should bolt right up.

[32ponchoWest]

Originally Posted by lrust

@32ponchowest, I have the same Hilborn 347-P-8 unit and I am considering options on how to use it. Can you share how you are going to convert to modern EFI? Thanks.

If I can figure out the fitment issue, I planned on having Fran over at Fox Injection convert it to EFI for me.

[694.1]

Second photo is of a 57-64 Edlebrock EP4B & a '58 intake. First is of a '57 head.
Looks like to me, you don't have a hole in your head!

[tom s]

That E intake has a freeze plug in the front you move to work for 55-60 and 61-64.Tom

[32ponchoWest]

Originally Posted by 694.1

Second photo is of a 57-64 Edlebrock EP4B & a '58 intake. First is of a '57 head.
Looks like to me, you don't have a hole in your head!

Thank you for the photos. The threaded hole is in the head, but not where Hilborn drilled their hole to supposedly work with this head.

[32ponchoWest]

Originally Posted by tom s

That E intake has a freeze plug in the front you move to work for 55-60 and 61-64.Tom

Tom, what do you mean by "E" intake? Thanks.

[tom s]

Edelbrock

[32ponchoWest]

Originally Posted by lrust

@32ponchowest, I have the same Hilborn 347-P-8 unit and I am considering options on how to use it. Can you share how you are going to convert to modern EFI? Thanks.

If not too much trouble, would you mind posting a photo of your 347-P-8 unit? Specifically, a photo or two of the front port area, top/bottom. I would like to compare it to mine in order to see if Hilborn drilled the upper intake bolt holes in the same location.

Have you tried to match it up to your heads yet? Do you have a 347 or 370?

Thanks for your time!

[32ponchoWest]

Another request....

While I realize '56-'60 heads are supposed to be interchangeable, I am wondering if Pontiac could have made small
changes between years, possibly resulting in my mis-alignment issue, or was this Hilborn's doing?

Now, my '58 heads have casting number 528511. I see that the '57 heads should have casting number 523298 or in the case of a FI engine 52(xxxx) - last four stamped on O.E. install.

Does anyone happen to have a 528511 head that they could take a couple of photos of for me so I could compare the positioning of the upper-two intake bolt hole locations to my '58 heads? It would be greatly appreciated!

[32ponchoWest]

Fel-Pro gasket # MS9498SH1

You can see it covers two holes on the head but matches the intake ports correctly. Using a felt marker, I scribed where the head bolt hole should be on the Hilborn base plate.

I am not 100% positive I have the correct gasket, although they claim it is supposed to be compatible with the 347 and 370 engines. Still, why would Hilborn drilled the hole where they did, when the unit was supposed to "fit" the head? I have seen two Hilborn 347-P-8 units and the bolt hole locations are the same as mine. There is some piece to this puzzle that is missing...

[32ponchoWest]

Originally Posted by lrust

@32ponchowest, I have the same Hilborn 347-P-8 unit and I am considering options on how to use it. Can you share how you are going to convert to modern EFI? Thanks.

Can you please post a photo of your 347-P-8 unit, specifically of the base plate so I can see if the bolt pattern matches mine? Also, what's the casting number on your heads?

Thank you!

[Jack Gifford]

You could try calling Ron's Fuel Injection. They used to be the go-to guys for Hilborn stuff.

[Skip Fix]

I have a buddy who has a stack EFI Hiborn unit on his 500" 383 bsed '68 Charger if you need any direction when you get that far. He's been pleased with the Holley ECU. definitely had to tweak some things.

[61 vent]

I have found, a similar Hilborn early Pontiac setup, other than the injectors, what is required for the system? I imagine a fuel pump.
What is a good price ? and what needs to be looked at prior to purchasing, for a 70-year-old unit? All butterflies are funtional. Thanks

[32ponchoWest]

Originally Posted by 61 vent

I have found, a similar Hilborn early Pontiac setup, other than the injectors, what is required for the system? I imagine a fuel pump.
What is a good price ? and what needs to be looked at prior to purchasing, for a 70-year-old unit? All butterflies are funtional. Thanks

Could you please post the model number and/or photo of the injectors? And, which engine are you planning on installing it on?