Somewhere, whether from HAMB threads or other sites, I have come away with the idea that there are 3 different 181 heads. Does anyone know their respective description and casting numbers so I can know what to look for? I've heard that the marine head is best; bigger ports, breathes better etc..
I would love to see or hear more on these Wico Mag conversions. You have my interest. Do you have any pics of what you have?
There are at least 3 threads on the HAMB about these engines. If you do a search about 181 heads you will find what you are asking for. I know I've read it here. Well ,That isn't as easy as I thought. I just did several searches and found one picture. https://www.jalopyjournal.com/forum/threads/iron-duke-in-a-model-a.1016706/#post-11491137 I know there was discussion on the Inliner International site but a lot of the pictures are gone. I'll keep looking.
Seems most everyone is high on the "marine" head but haven't found out why. If its the only 8 port head I'd get it. I've read that the "marine" 181 crank is manufactured from better material to withstand the high rpm usage most boats are subjected to. Head also?
I am not very good at picture uploading, but I will look at the spare Wico/Chev II that I have on the shelf get a couple of pictures. I will also take a closer look at how it is put together. What part of Iowa are you located in ? Have fun.
@tractorguy Thanks. I am Just east of Iowa City about 10 miles Just south of West Branch, former home of Chassis Engineering.
I'm sure Tom Lowe (12 Bolt Tom) could set things straight on the head choices. I seems that there are 3 181 heads. Two are 8 port and one is better than the other. Since all of the 181s are industrial engines I really doubt that the marine engine would have different metal from the forklift and others. The good head may be more likely to be a boat application as they may run longer at higher rpms. It is more likely to be a date thing.
Six Ball...my intention is to talk to him about the heads, perhaps even get him to work on mine. Thanks
Well, looky here: https://www.ebay.com/itm/62-63-Chev...341874?hash=item2ad95c7632:g:nHQAAOSwv7ldzJuf So, now two questions for you guys: Why do these pistons have four valve reliefs? And again.. What is the deck height of an uncut, original 153 block ? ( Hint. It would be the same, give or take , as a 230 6 cylinder.)
The four valve cuts are probably because they are the same as the 307 V8 pistons. This is a 250 six piston in my 153 with 181 crank. This is a 307 piston in the same engine the only ones I've see with two cuts. Both would work fine by decking the block a bit. Here is the Ross forged flat top for the 250 sold by 12 Bolt Tom. I'll run these they stick slightly out the top but will be fitted to zero deck. Here is what was in my 153 when I got it. .050 down the hole with 153 crank. Here is one of the original ones on the 181 crank. I don't know what any of this means about what will work in a stock stroke 153. I know I had the deck height number when I was working on this. Got boxes of pistons but a few more blocks to fill.
Thanks for the pictures. The reason there are 4 valve reliefs on the original piston is because GM used V8 pistons 283 pistons , to be specific. But wait. I was told by two folks here that you couldn't use 283 pistons. Okay, let's look at the details. Nobody came up with the original 153 deck height. Understandable , because I couldn't find it either. I did find that Leo Santucci's book has the 230 deck at 9.150 . I can't imagine why a 153 would be different. Same stroke, rod, piston. Take half the stroke; 1.625 Rod 5.700 Comp height, 153, 283. 1.779 Equals 9.104 That leaves the piston .046 down in the hole..Sound familiar?.. You could mill and square all that away, and use about a .040 gasket..What's the problem? BTW, the W235 P Sealed Power is a replacement for the 153, 230, and 283.. The 250 has a different stroke and a dish, made for that application. No need for four valve reliefs there. Did I answer all my own questions now ?
The 9.150" sounds familiar. What messed with me for a while is that replacement oversized pistons have a lowered compression height to compensate for the larger bore so as not to raise compression, which is usually what we want. I don't know how much can safely be taken off of these blocks but some would have to be removed just to keep the piston at the stock height. But yes, I think you did answer your own questions.
So strange, I looked in my 67 Chevy repair/overhaul books, they have everything but the deck height. I scoured the W.W.W. and could not find it there either.........strange.
I'm guessing you're attempting to get the quench to the .030-.040 desired ? If you do that , assuming a stock head c.c. ,what sort of compression are you looking at ??
I did it at 0 deck, .035 gasket, -4 cc for reliefs, 69.9 cc chamber, NHRA minimum, .030 over (3.905) = 9.75 c/r
That should add some power !and be pump gas friendly . So you're going to cut the deck .040 ?? and use the 2- valve relief pistons & stick with the 153 crank ??
Nah, I'm just playing around with numbers, presently. What I would do with a 153 would probably be extremely boring to the hot rodders here on this site.
Are they making these any more? I have this one in mint shape that I may sell as I am making my own intake... -Shiny
For the record , I did write it. I thought I sent it . Now I don't see it .I must have had a gastric attack at that moment. I'll try again tonight..Working on O/T race car at the moment.
There's been mention of different oil pans for these motors. Any direction I should look for a rear sump oil pan? The one I currently have is sorta a center sump pan.
I was lucky when I built my AVATAR that you could still go down to Chevy and get a center sump pan (which would probably work for you) across the counter that came in a Step Van. Try some of the suppliers that specialize in early GM parts. Check out the pans used on the Mercruiser Marine engines (don't tell them it is going in a car). My Mercruiser engine was from the early seventies and if I remember correctly (also a memory from the early seventies) it came with a center sump pan. Charlie Stephens
Mine is the only rear sump pan I have ever seen. I came by it on accident when the guy I got the engine from said, "Here , you'll probably want this and here's an oil pump with the long pickup for it." I think some of the 151 (IronDuke) pans are rear sump and they can be modified to work. I think the difference is the rear seal.
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