Inliners International Forums General Discussion Hi Performance GMC intakes

HI guys, wasn't sure where to post this exactly. I have a GMC 228 and I'm in the UK, taken years to find an engine so I'm on the hunt for a intake manifold now. Im building a little race car on a model A chassis so something "period correct" would be great.

Currently have a friend over in the US who can bring something back, if anyone has anything please let me know.

Thanks in advance Joe

Would a Triple Sidedraft Weber intake be "period correct" for you?

after a 3x1 or 3x2 style set up if possible. Thanks anyway

A 2X1 would be plenty for a 228 and probably easer to find. two Zenith singles would be fine.

thanks for the info Beater

You are welcome. A lot of people don't think the 228 is worth messing with because the rest of the GMCs up the line have the same outside detentions. But it is a good strong engine and if there are cubic inch restrictions say in a vintage class it will do well. Also if it is what you have and you like to tinker it can be improved. It will accept the 4" stroke crank of the tall dec engines. By boring and using custom pistons and stock rods you can get around 260 inches. You might find an off the shelf piston. It may not make dollar sense but it could be fun. Remember it is not a high RPM engine and you'll want to gear for the RPM range. Also it has thick cylinder walls and a strong (for the time) bottom end. It will take quite a bit of boost say from a vintage supercharger. It will make your Model A rails ring!

Interesting concept with the charger beater- I have a few vintage chargers I have been watching on eBay.

I found a couple 302 engines in the U.S. But it's going to cost £500 plus import to bring one over, seems a bit excessive so I guess I shall have to work with what I have currently.

With the 4" crank- is it advisable to have a better head to? The Big port head? The chap with this 302 has a spare head and crank so I could have that posted back over if that's going to be a better budget option. Is it not possible to run off the shelf Pistons I have seen advertised? If I run the head and crank can I run after market Pistons designed for this application?

Think the A chassis will need boxing for sure! Thanks for your help

I agree with Beater - sometimes it is cheaper to start with what is in hand - especially if it is known to be sound. And they are heavy bits so shipping just piles on to the cost equation when shopping for an alternative.

As for pistons if you bore and stroke a 228 you are likely headed down a path toward custom pistons.
Old GMC Trucks Page


The 228/248 blocks are shorter then the 270/302 blocks - but they use the same connecting rod length. So the piston needs to be crafted with the pin closer to the top of the piston to compensate for the shorter deck height.

With custom pistons you can have the block prepped and measured - and then order slugs that are an exact fit.

regards,
stock49

I agree with stock49 especially as to custom pistons. Be careful with main bearings as they have different bores. There are 2 rod bearings. I think the only difference is the width of the tab that fits the notch in the rod. Thus there are wide and narrow notch rods. otherwise all GMC rods are the same. They are strong and good for all the power you are likely to make.

There are 4 different heads. This link tho Patrick's catalog shows the differences.
Patrick's

I have been running the later 270 style head since 1978 and find it works fine for a warmed up street pickup. You only need the big port heads on an all out race motor. Some port work and bigger valves will do all you need otherwise. Bill Fisher did not recommend the big port heads for a mostly street engine. A supercharger will make the big ports unnecessary. It is a shame that no-one has written a GMC speed manual since the 50s. A lot has been learned since then and newer seals, valves, etc are available.

The compression distance is only off by 3/32" (.093"). The 256 piston has the right deck height for the longer stroke but it's +1/8", and the dome design must match your combustion chamber type.
The increased 270/302 crankshaft stroke only adds 4.9% to the displacement, very expensive in terms of power per dollar considering the crank, custom pistons, and balancing.

Beater, there are also two different style connecting rods with the main difference being the diameter of the wrist pins. So be careful when purchasing pistons and verify which connecting rod you have.

Beater, as for the GMC speed manual, I just have several more pics to take and mine will be completed and ready for the printer.

stock49- thanks for the link there, that will be very helpful. I'm not familiar with engines and spec's will be great to get that printed out and get learning. thanks for sharing.

Beater- spent a lot of time looking on the patrics website, was great for the casting part numbers too. I was very saddened to collect the 228 after hunting for ages, to learn I had the least desirable set up possible. But after what everyones saying thats much better than nothing. I didn't pay much for it too so it seems a great use to work from.
So your suggesting spend the money on setting up a super charger, rather than bringing a head and crank over? Really work with what I have and improve upon this base. The car won't be used on the road at all, sticky for "race" purposes.

Panic- thanks for that, as above my knowledge base of engines and there working is very slim. Im more metal working based so this is the only grey area of the project. The way you put that sounds like a big head ache, wallet ache for not much of a return. Would you suggest new lighter, off the shelf pistons and a super charger?

CNC-dude- please can you put me down for one of your first copies, be great to read up and learn the new wave of information since the 51 edition of the hop up manual

The cheapest supercharger is the fairly common Eaton M90 but needs some fabrication to supply the manifold, and also to adapt an intake (since they are all rear mount TB).
A centrifugal is more $$$ but may be easier to mount since the output just goes to a std. carburetor.

"It may not make dollar sense but it could be fun." from post #92686. If winning races is important it will cost a lot of money no matter what kind of racing you do. There are people out there now who will spend a ton of money for the most obscure win. One reason LSR is so popular is that you can have fun just improving your own speed. Records are nice but not necessary.

Yeah Scott I forgot about the wrist pin thing. Did you cover the MOPAR rear main seal? I want a copy too.

A McCulloch would be easy to mount. A friend had one on his 302. Here is a link to a thread on the HAMB where a guy put a Graham supercharger on a 9N Ford tractor motor. Read through to page 7 where he raced it at TROG to see how much the boost helped.
Graham/9N

I have found a couple Wade supercharger on eBay, they end tonight so I shall see how those go price wise. Its a tricky one as I can't find much online about rebuilding these. An m90 would be a good budget way to go but I can't get passed it looking too new being strapped to the engine, seeing as I'm trying to build a fairly strict era specific car this would be the first "new" part

thanks for the link, nice little write up with some fab work in there too. just what I like to read.

McCulloch has sent a few bay links up- any ideas on these guys? Mounting and the fabrication is no trouble what so ever for me.

https://www.ebay.com/itm/McCulloch-Super-Charger-VS-57S-103211-/222680878678

https://www.ebay.com/itm/Paxton-SN92-Sup...r-/222675294854

https://www.ebay.com/itm/57-58-STUDEBAKE...R-/132203696352

https://www.ebay.com/itm/Studebaker-Paxton-SN-60-Supercharger-R2-R3-/352186702360

Be careful, the Paxton etc. had drive lubrication problems when turning high RPM back in the day, and the internal parts are both fragile and expensive.

http://www.vs57.y-block.info/vendors.htm
http://victorylibrary.com/VS57/vs57-carb.htm

Your a star Mr Panic, thank you very much for the links. Just see there's a UK parts/rebuild guy on there too. Already dropped him an email

Managed to reconstruct some of the illustrations
http://victorylibrary.com/VS57/VS57.htm

Thanks Panic, That is some good information. I don't like putting the carb in a box where the leaks can go unnoticed until the box is full and adjustments are difficult at best.

Finally picked up a McCulloch at a really good price, the bay hunt is over.

Putting a few bits together in a box to bring back to the UK, does anyone have any ideas what to use carb/throttle body wise? Be quite nice to run some EFI set up but I can only find parts for 1000BHP cars. In a dream world it would be great to run something I can see whats happening on a screen. Any advice is much approached as ever you clever chaps

Some hints on carburetor selection on my site here: http://tinyurl.com/yc42v74r
More info: http://vs57.y-block.info/history.htm