Questions about block casting #1254083?

[Kidslelleen]

There was a post earlier this year about the 1254083 block, but the answers really didin't cover my question or maybe the thread go a little sidetracked.

Anyway, I have this block in a 71 Jeepster Commando. The engine is an Odd Fire (yes, it is an Odd Fire) and I would like to keep the Odd Fire firing order... just because. I would like to put some 79+ heads & appropriate intake on my block, but I don't know if my block will work with the "newer" heads. My concern is that the water ports in the block and 79+ heads won't align correctly. The Team Buick website (and others) indicate that the 1254083 block was used from 75 - 87 in all types of configuration (2BC, 4BC, SFI and Turbo). So my assumption (and I know how to spell assumption) is that the "newer" high port heads will work with this block. Will they, for sure?

I have an opportunity to pick up an 86 NA 231 block (Olds, I believe) at a fair price to do a swap of the crank, rods, and camshaft (maybe 350 flat top pistons) from the Odd Fire to the 86 block. FWIW, I would probably go with a 212/212 (260H) or 218/218 (268H) camshaft. If I need to use the 86 block, that's okay. I just don't want some unnecessary cast iron in my shed that I would probably never use, so just keeping my 1254083 block is my 1st choice. BTW, I have a TH400 currently as my transmission.

I'm not planning for a 300 HP engine or rock crawling, I would just like some more safe cruising RPMs and better throttle response. Of course I am planning on doing the proper build on either of the engines: oiling, porting & polishing, larger valves, single plane intake, etc.

I don't have enough room by my firewall for all of the plumbing that a draw thru turbo would need, and I don't think I want to go in that direction. I also was looking at a 4.1L donor but they are as scarce as ...

That's the short story. Your comments and suggestions are appreciated.

 

[No disintegrations]

But changing only the engine won't do anything for cruising rpms.

 

[Kidslelleen]

But changing only the engine won't do anything for cruising rpms.

Maybe I didn't clarify my intentions enough. I want to use a higher duration cam (either a 260H or 268H grind or maybe a custom grind), larger valves (1.770 I, 1.50 E), port & polish heads, port match, headers, single plane intake, 4BC, high compression pistons, upgrade stock oiling system, and all the other important but maybe small things to get more HP and RPMs. Sorry if I wasn't more specific.

I would just like to know if I can use this block with the high port heads.

Thanks

 

[dank GN]

why wouldn't you be able to ? also why don't u just build a 4.1 block . everything fits on them just like the 3.8 blocks but more displacement

 

[Kidslelleen]

why wouldn't you be able to ? also why don't u just build a 4.1 block . everything fits on them just like the 3.8 blocks but more displacement

I don't know if I can or can't. That is my question, even part of the title of my original post. Do you know for sure that the 1254083 block will work, without hassle, with the high port heads (79+)? If you know, puulleez inform me.

I have given the 4.1L some consideration, but as I mentioned in my 1st post, for me, I haven't been able to find one for a price that I am willing to pay. Previously, if I could find one, I would probably put 3.0L flat top pistons in it to get the compression up. They (4.1Ls) seem to be really hard to find (for me). Let me know if you know where I can get at least a core of a 4.1L. I would appreciate it.

Edit: Stupid me, 3.0L pistons are too small for the 4.1L. I would probably need some Chevy HC pistons, but then again I would need to consider bore, pins, and stroke height. Plus whatever else I don't know.

 

[dank GN]

I have acouple good blocks . I have a 4.1 block , and a hot air turbo block which I know would work and would be stronger . I’m not sure about the block you are asking about . I would try an get a newer stronger block like the 2 I have . Shoot me a message if u want one of them .

 

[ek02]

According to Pat Ganahl's V-6 Performance book, the 1254083 block is a 77-79 block and only 77-79 heads will work on that block. 1980 and up heads are different. The bottom line is to use the heads that come with the block. Any head will bolt to any block, but the water passages have to line up. Attached is a scan of the section on heads and blocks. I would use the even fire block and heads. I've had odd fires and they are really rough running and there is no strength advantage to the odd fire engine according to Ganahl. If you have the heads that came with the 1254083 block, port them and use them. They should be high port heads, just not like 80 and up GN heads. If you can find a head gasket that matches the block, lay it against later heads to see if there are any mismatched passages.

 

[Kidslelleen]

View attachment 312462 According to Pat Ganahl's V-6 Performance book, the 1254083 block is a 77-79 block and only 77-79 heads will work on that block. 1980 and up heads are different. The bottom line is to use the heads that come with the block. Any head will bolt to any block, but the water passages have to line up. Attached is a scan of the section on heads and blocks. I would use the even fire block and heads. I've had odd fires and they are really rough running and there is no strength advantage to the odd fire engine according to Ganahl. If you have the heads that came with the 1254083 block, port them and use them. They should be high port heads, just not like 80 and up GN heads. If you can find a head gasket that matches the block, lay it against later heads to see if there are any mismatched passages.


View attachment 312462

Gold!!!

Thank you very much. That is the Exact information I was looking for (but not the results). I really, really appreciate the effort you put into this.

So, I think I'll get the 86 block and use that as my base build. That way I should be insured that any machine work done on the heads should follow standard protocol and me not having to worry about unexpected "gotchas" while performing head machine work and porting, which would probably include (but not be limited to): larger valves, three angle valve seats, head gaskets, great expectations and etc.

Yes, I have the complete 77(?)-79(?) engine, with all it's warts.

John Thawley in his "Buick Free Spirit Power Manual" wrote that pre-79 heads should only be used as door stops. I guess the 79 heads should also be in that equation.

You are a good person and I can't thank you enough.

PS: I had just purchased Pat Ganahl's book, but it is still in the mail. I guess I should have waited until I read it before I posted this.

 

[ek02]

The 79 heads should be high port, but may not be as good as the 80 and up heads. Using the later block will allow you to use any parts that work for a GN, like aluminum heads, gaskets, forged bottom end parts.

 

[Kidslelleen]

The 79 heads should be high port, but may not be as good as the 80 and up heads. Using the later block will allow you to use any parts that work for a GN, like aluminum heads, gaskets, forged bottom end parts.

Hmmm, some type of fuse deleted my post.

Anyway, using my current block seems to be the easiest way to go. Finding the correct head gasket could be problematic, especially after doing a quick google on the HG part number that Pat refers to.

I'll give it a shot and if I have major problems I'll go back to Start (and not collect $200).

Thanks for your input, mucho appreciated.

 

[b4black]

I was going to suggest getting that book. It covers the early engines well and most of the book is about the Buick V6. I believe it's copyright is 1982 (ish)

https://www.amazon.com/V-6-Performance-Pat-Ganahl/dp/093147213X

I don't think there is a big difference between 1979 and 1980 heads. In general, the heads and blocks were tweaked each casting, so the later the better, but unless you are building an ultra high performance engine, the differences are small.

 

[Kidslelleen]

Okay; I finally received my copy of Pat Ganahl's book. I read the page that ek02 had so nicely scanned for me. As a matter of fact, I re-read it several times. I have come to the conclusions that I am not a very good grammar student, and maybe, just maybe, Pat could have chosen better wording. He states, "... Either heads will fit the interim blocks; only 77-79 heads will fit the SUBSEQUENT block without causing water leaks. ...". I guess I didn't know what "subsequent" meant. Maybe the word "later" would have been clearer to me.

On Page 82, Pat is writing about heads (He is writing about the 79+ High Port Heads): "Simply bolting these heads onto the '77-78 blocks (which I have) will greatly increase performance,..."

This explains the casting number 1254083 being documented as being used during the '77-82 years. If I can find some acceptable '80+ heads for a decent price, I'll go that way. I still have an opportunity to get a 231 core from an '86 Olds for ~ $150, so that is another option for me. I just don't need extra cast iron sitting around and I like to be on the cheap side since I have a fixed income. I'll match the 80+ 231 head gasket with my block before I go and get some heads that I really can't use.

I'll probably get both the intake and exhaust manifolds to go with my proposed setup. I am planning on installing a 4 barrel carburetor versus my current 2-Jet. I have a Weiand / Yunick intake manifold but I would prefer to use the spread bore Q-Jet. The Weiand intake was manufactured for a square bore carb like a Holley, and I don't currently have an adapter plate for a spread bore carb to a square bore intake. Plus, I really don't want to mess around with adapter plates, gaskets and etc if I can avoid them.

I'll probably put the Weiand up for trade for a stock 4.1L intake in exchange. That's probably a little later.

Thanks for you help, folks. It doesn't go unappreciated.

 

[ek02]

There are two Weiand intakes for the V6. The difference is one of them has an air space under the port runners and the water outlet is on the top instead of the front. Which one do you have?

 

[Kidslelleen]

Water outlet is on the top. Inlet is on the front. It's the "Street" version, especially since there is an EGR valve on it instead of a blanking plate. The EGR is just a "bolt on - bolt off". I don't have the blanking plate for it nor do I have any adapter plates.

 

[ek02]

Thanks. I had one like it but sold it. I'm looking for the other type. You could put a Q-jet adapter on that manifold and use it on your build. It will work better than a stock 4.1 manifold.

 

[Kidslelleen]

Thanks. I had one like it but sold it. I'm looking for the other type. You could put a Q-jet adapter on that manifold and use it on your build. It will work better than a stock 4.1 manifold.

Sorry that you can't use it. I guess the other Weiand input is scarce also. Anyway, thanks for the heads up.

Just asking, do you have a recommendation for a 4 hole adapter to use with the Q-Jet? The only one I can find online is the Edelbrock. I guess I would need to flip it over and grind a little. I could be wrong.

 

[ek02]

The Edelbrock should work. Summit has one also for a lot less money.

 

[oddmonte]

I have the same intake. The guy I bought it from must have died before he shipped the top plate to me. Adapter plates will not cover the opening. The opening is larger than any adapter you can buy. I tried that first. I ended up making one for mine out of quarter inch plate.

Good luck to you.

 

[Kidslelleen]

I have the same intake. The guy I bought it from must have died before he shipped the top plate to me. Adapter plates will not cover the opening. The opening is larger than any adapter you can buy. I tried that first. I ended up making one for mine out of quarter inch plate. View attachment 313080View attachment 313081 Good luck to you.

That what I thought. The opening on the intake is large with just a small platform to put a carb or adapter plate on. I heard the Weiand DID make adapter plates for the 7541 intake but I think getting one is "Good luck finding one".

What did you use between the intake and the plate you made, RTV or a homemade gasket?

Thanks for sharing.

 

[ek02]

The groove around the flange is for exhaust gas from the EGR valve to enter the intake. The home made plate is the best solution, then put the adapter on top of it. You can also make a small plate to block the EGR valve after removal.