Difference in SBC intakes

Hello, I was just wondering if anyone can tell me the difference between a '57 - '86 intake manifold for and SBC and an '86 on intake manifold? Why wont the '86 later work on say a '57 - '86 block. The reason I ask is I have a '76 block and I think someone ripped me off by selling me an '86 afterwards intake as it won't bolt up in the middle four bolts.

 

The heads will decide which intake to use, not the block. Are the bolts on the center four bolts, verticle or at an angle?

 

Nobody ripped you off ...

You just bought the wrong manifold

.

 

Yup the one on my heads are on an angle and the ones on my intake are not on an angle.

 

The guys I bought it off of worked one General Motors cars for years (high performance mostly). They told me this intake would work for a stock '76 block. I believed them. The told me it was an '57 - '86 intake.

 

I've got newer center bolt style heads and am using an old style Offenhauser tri-power intake. The center 4 bolts are at a different angle (more straight up and down) but you can elongate the holes and make some wedge washers and it will bolt up. I'm not sure if you can go the other way but I don't see why not, it just takes a little cutting and fitting. The angle of the heads that the intake bolts to is the same. I've been running mine for over a year and no problems. If its not a special intake I'd look for the right one to fit your heads. I wanted Tri-Power and got the intake at a good price so I made it work. It's a matter of how much work you want to do to make it fit, old style intakes are pretty cheap for SBC engines.

 

Like mac762 said, the year block doesn't matter. What matters is the year of the heads. Sounds like you have later heads (87 - 95) and an early manifold (55 - 86).

 

Nope I have a 1976 L82 Corvette 350 pulled out of an all original 'Vette. Nothing has been changed. The heads are stock. What do you guys think about taking my powerdrill and drilling the center fours at a bit of an angle? Or is that to redneck?

 

Read my first post.

 

How about post up block and head #'s and we'll tell you what you have.

 

What is the intake, an Edelbrock Performer style? You can probably sell the '87 and newer intake for more that it will cost to replace it with an '86 and earlier intake.

 

I'm not familiar with the newer intake at all, but from what I can "guess", you can bolt it on with the bolts that do line up with good gaskets, and judicious application of Ultra-Black silicone and be golden. Be sure to tighten the bolts a little at a time while moving around from bolt to bolt for a nice even install

 

Several intakes are now made with elongated center holes to allow use on either generation heads. Most come with wedge washers to compensate for this but I have seen many owner modified intakes run with zero problems. Take your time and remove a little bit at a time with a die grinder or round file.

 

I was a line mechanic for a GM dealer in the early-mid 90s and I had pretty much full access to the engine cores we pulled out. I rebuilt a lot of later core engines and installed them into earlier vehicles by elongating the two center bolt holes on each side of the intake. Never an issue with this at all.

 

I just "bent" a larger diameter washer, and ground the bent down part somewhat flat; used allen head bolts so the bolt head "corners" would'nt catch. It worked out fine. This was an earlier 350 block, with 305 FI center bolt heads (the dreaded swirl port), and an even earlier Wieand open plenum intake manifold with the center 4 bolt holes elongated. As someone else mentioned, go a little liberal with the RTV sealer aound the center 4 bolts. Runs and revs good for a street motor, despite the swirl port heads. This is for a 51 Bus Coupe I'm building for my nephew, and he does'nt need too much power, too fast, for too long; if you know what I mean. Butch/56sedandelivery.

 

What are wedge washers?

 

I know what I have a bone stock 1976 L82 w/ stock '76 L82 heads.

 

I live in a country where no one is into hot rods, low riders, muscle cars, customs. etc. Everyone just buys a new SUV over hear.

 

Hey Groucho not 100% what you are saying in this post. I glued on my gaskets and then put the monifold on and found out it won't work. I used brand new Milodan Chevy/Chrysler bolts with new washers. It was a no go. The manifold I have (Edelbrock Performer RPM Intake) has the center four bolts going up and down. While my heads the center four bolts are at an angle (Stock '76 heads).

 

Thanks I am going to try this when I get home from school. I think I will use my Mikita power drill first then go in with my Dremel 400 and then some files.

 

Thanks will try driling into it when I get home today.

 

Thanks. I don't think the washer thing will work though. I mean I tried that and the bolts would just not go in at all. I think I have to drill it out.

 

Won't it bolt up with the other 8 bolts? Leave the 4 odd ones out maybe

 

Any chance he has a vortec manifold? Keith

 

I drilled out the middle four holes perfectly now the rest don't match up. Might have to do all of them.

 

Can you put up a picture of what you are working with?