[Steady Eddie]

Some other cool stuff (as mentioned above):

The head that StrokerS10 mentioned (#10112514) is a Code A cylinder head.

Here is a useful link to the GM casting numbers, it is a .pdf file, and you can do an Adobe Reader "search" for that 10112514 number and find other GM vehicles, with the same head...

http://www.enginepartswarehouse.com/enginecatalog/GENERALMOTORS.PDF

Use this for a guide when junkyard cruising for Iron Duke motors and things, I was surprised to find this Code A head (as an OE part) in so many different rigs..

 

[Steady Eddie]

StrokerS10 says the larger intake valves (that are the right length) are NOT Pontiac, but are Oldsmobile 350 V-8 valves...he mentions "different valve seals", but does not mention re-machining the heads or even if it is needed???

How many of you thought that a GM 350 was the same as all other GM 350s?? According to StrokerS10, NOT.
Reading between the lines, if they were all equal, then any 350 GM intake valve (of the right diameter) would work--??

 

[StrokerS10]

OK kids now that you know one of the "A" code head casting numbers I'll give you the other, it is 10044485. The difference between these two heads is not very significant but there is a difference never the less. The 10112514 has a slightly better intake port design. However through proper porting you can make both of these heads identicle. Got it?

Now for the confusing part. There are "A" code and "U" code versions of these two casting number heads. GM starts with the same casting number and drills the head bolt holes in different locations. YOU CANNOT PUT A "U" CODE HEAD ON AN "E" OR "A" CODE BLOCK OR VICE VERSA! There is a quick way to tell the difference between these two bolt patterns but I know if I try and explain it here I'll lose you, so instead just get an "E" or "A" code head gasket (same gasket fits both) and check it against the head.

One more piece of the puzzle!!!!!

 

[Steady Eddie]

So--

A novice would be able to tell the port differences between the two A code heads??

I would think that you'd need a 514 head and a 485 head, side by side, on the bench to tell the difference.

In my other post (w/.pdf), you can see the 485 head listed right along with the better 514 head--same-o same-o.

But only StrokerS10 would know that one was better than the other..

 

[StrokerS10]

Ok students I hope you have all done your homework and are ready for the next lesson!

The "good" 485 and 514 heads are only found on mid year 1991 and up S10s and S15s "A" code engines (GM changed from E to A code in the middle of 1991) and on 1990 and up "R" code passenger cars. Passenger cars got the "good" engine before the trucks. Thats how GM uses up inventory before upgrading to the better parts.

The intake manifold that fits these two heads is the same for all "R" (1990 up) "A" (mid 1991 and up) and "U" (1990 and up) engines. This intake has casting #1066656 written on it. It also has a machine # on it 1066657. I believe that GM also used this same casting on another application but machined it different, can't remember. Just make sure the one you use has that machine # on it. You cannot use that manifold on earlier heads as the bolt pattern is slightly different and the intake ports are moved slightly. CONFUSED YET??

The throttle body that comes stock on this intake manifold has a bore of 1.81" (46mm). The earlier (E) engines had a throttle body bore of 1.73" (44mm). IIRC the 46mm TB flows about 250 cfm give or take. The 44mm TB will bolt on to the later intake as well. Both are interchangeable as far as all connections go, however I would not put the larger TB on the earlier intake manifold as the bore of the manifold is too small for the later TB. GOT IT?

In other words if you have an earlier 88 - 91 "E" code engine you can bolt on the later "A" code head, intake and throttle body and everything will bolt back on and plug in and work just like factory.

Your earlier "E" code engine will now be identical to the "A" code engine except for just one more part. Maybe I'll share that with you sometime!

Until then you can all "Go outside and play" its "Recess time"! I'll ring the bell when it is time to came back in.

 

[Steady Eddie]

Great info--thank you..

Got any idea about how much air flow you could get from a 51 mm TB?? These are off a Corvette Crossfire TBI, one is wired for the stock harness and the other is a "dummy" with no electronics..

http://cgi.ebay.com/ebaymotors/Cros...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[Steady Eddie]

Ok students I hope you have all done your homework..(I did..)
Your earlier "E" code engine will now be identical to the "A" code engine except for just one more part. Maybe I'll share that with you sometime!

=========

The A code engine has a different part number for the ECU/Brainbox, with a different chip...is that it??

 

[Steady Eddie]

Great info--thank you..

Got any idea about how much air flow you could get from a 51 mm TB?? These are off a Corvette Crossfire TBI, one is wired for the stock harness and the other is a "dummy" with no electronics..

http://cgi.ebay.com/ebaymotors/Crossfire-51mm-bored-rebuilt-t-body-82-84-Corvette-Z28-_W0QQcmdZViewItemQQhashZitem35a678a3b1QQitemZ230426190769QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

==============

I just looked this up:

51mm = 2 inches

Which is the same as the bore size of the famous (or infamous) Holley 300 CFM aftermarket TBI!!

 

[palebrand]

what a nice Christmas Gift it was

 

[StrokerS10]

=========

The A code engine has a different part number for the ECU/Brainbox, with a different chip...is that it??

The later S10s do use a different computer which is not interchangable with the earlier units. It is of a completely different style and with different electrical plug ins. I don't believe there would be any advantage to the newer design computer, even if you could use it. Just install a new chip from "tbichips.com" and I can assure you that you will have all the performance from your "Duke" that you can have from either computer.

The "one more part" that I was refering to was an "engine" part, which is the last item needed to convert a "E" code engine to an "A" code engine. That part would be the "Camshaft".

Both the "E" code and the "A" code camshafts share virtually the same timing and duration specs (minor difference), but the "A" code camshaft has slightly more lift .434 vs .404.

Now if you are really serious about performance then a "bigger" camshaft would be in order. It needs to have more duration and even more lift. But be aware, go too far and it won't pass smog if you live in a state which does inspections.

There are quite a few performance hydraulic camshafts available for these engines but most of them are flat tappet cams not roller cams. I would always spend the money and stay with a roller cam as there are several advantages to doing so. "Amotion" had a few performance roller cams available at one time but they have since closed their doors. Doug Frieson from Amotion will still custom grind you a camshaft but it is very expensive. A cam and lifter set will run you over $400.

I am having my own custom grinds done locally for about $100 as long as I supply the core. I am having one ground with a little more duration and quite a bit more lift than the "A" code camshaft but it will still be able to pass California smog ....as long as I don't tell them that the camshaft was changed. And besides what they don't know won't hurt them!

Now go outside and play some more!

 

[Steady Eddie]

Thanks for more great info..

The intake valves are 1973-76 Oldsmobile 350--1.875" dia..

 

[Harry Canyon]

Quick and simple question.

Can I put this intake on a 88 E-Code head? It appears to be from a carb'd Jeep.

http://cgi.ebay.com/ebaymotors/Jeep...r_Truck_Parts_Accessories&hash=item2c59e85817

I'll look up the gaskets tonight at work and see if their the same part number. I'd bid now if I knew for sure.

 

[Lilchief]

StrokerS10: Some more brain picking. I'm working on a SD4 block with a 3.0L mercruiser crank and 437 SD head. I'm wanting to run a turbo on it with 15-20 lbs of boost (T35?). What CR would you recommend if I also use water/methonal injection and/or water/air IC. I'm thinking 9.0-1 to keep road drivability good. That's considering is an aluminum head. I'm also thinking of getting the head ,flow tested, to help determine the right Turbo. The goal is 400-425 whp at 7K. What's your ideas ?
Thanks Rick

 

[s10kid17]

http://cgi.ebay.com/ebaymotors/ws/e...0696500555&viewitem=&sspagename=STRK:MEWAX:IT

 

[Alsfarms]

Ok....., I have tried to search this thread, on HP builds for the 2.5, for information on chamber size on a stock 1992 2.5 head. Can someone point me to that information? I am getting real close to getting after some machine work to install the 181 Marine crank in my 1992 S-10. I may be destroking the crank just a bit to make it work. I just picked up a set of 6" Carillo rods.
Al

 

[StrokerS10]

52 cc.

YOUR GUNNA NEED LONGER RODS!!!!!!!!!!!!!!!!!!!!!!!

Unless of course you want to see them sometime.......
THOUGH THE SIDE OF THE BLOCK!!!!!!!!!!!!!!!!!!!!!!!!

:bash:

 

[Alsfarms]

52 cc.

YOUR GUNNA NEED LONGER RODS!!

Thanks for the CC spec. I had it in my head the 1992 2.5 had a combustion chamber volume larger than 52. HMMMMMMM

I have read through your responses a couple of times, good information. I have (2 ea) 181 cranks and hope to make one runner and have one parts set to offer for sale to help out on my costs. Another fellow, off this forum with valid experience, suggests I can use the 6" rods but like you, said 6.2" would be better.

Regards, Alan

 

[StrokerS10]

52 cc.

YOUR GUNNA NEED LONGER RODS!!

Thanks for the CC spec. I had it in my head the 1992 2.5 had a combustion chamber volume larger than 52. HMMMMMMM

I have read through your responses a couple of times, good information. I have (2 ea) 181 cranks and hope to make one runner and have one parts set to offer for sale to help out on my costs. Another fellow, off this forum with valid experience, suggests I can use the 6" rods but like you, said 6.2" would be better.

Regards, Alan

Alan,
Read post #39 as many times as it takes to FULLY understand what was said in it.

I will also give you a formula for rod length in the "Duke" block...... notice I did NOT say "Super Duty Block"!!!!!!!!!!!!!!

Minimum rod length for the Duke block is 1/2 the stroke plus 4.375". Got it?
Ideal (perfect) rod length for the Duke block is 1/2 the stroke plus 4.5" Ok?

Many times you can not fit the "perfect" length rod in this engine due to piston availability so anywhere between the "minimum" length and the "ideal" length will work fine.

Unless you destroke the 3.6" (181) crank to 3.25" DONT USE THE 6" RODS!!!!!! P.S. You cannot destroke the 181 crank that far anyway so don't try it. (unless maybe you have some 1.75" [or smaller] journal dia. rods! LOL)

If you want to know how/why this formula works send me $1000 and I will tell you. OR........ JUST TAKE MY WORD FOR IT........ BEEN THERE DONE THAT...... TRUST ME AND I WILL SAVE YOU A LOT OF MONEY!!!!!!!!!!!!

If you still intend to go ahead and do it after reading this and post #39, ask me and I will show you a completey DIFFERENT way you can save lots of money!

 

[Alsfarms]

Hey.....I read your #39 again. I do understand your formula and the relationship to rod length. If I ever get a chance, I would like to chat on the phone about that and a couple of other items. I can see where the stock marine comes out at 5.7. I am convinced and will be looking for small journal BBC rods, either 6.2 or 6.3. My crank rod pin being 2.1 will give me a little room to play, tune stroke as needed, with to get the best piston and squish fit possible, and have the proper small journal. Let me ask you another question. The stock 181 marine rod is 1.035 at the big end. Most of the aftermarket rods are under 1. and closer to .970 or there about. HMMMM, that does not appear to be a doable thing. What do you suggest? I am not a serious race guy so I don't know the acceptable tolerances. If you have time, share some more wit and wisdom regarding rods and piston types.
Alan

 

[Lilchief]

StrokerS10: Well I dropped off my 437 head at the engine builders the other day to get some flow numbers. We discussed the middle and late mercruiser cranks. And came to the conclusion that the later model would be the best even though it's more expensive. Would have a wider selection of rods (SBC) and possibly stronger. The middle crank would require custom rods and cost more than the late crank. We also discussed the CR , 9-1 would work with 91 octane keeping the boost under 10 lbs and boost to 15 lbs on race gas. The 437 head had 2.125" intake valves, isn't that big block size? It was also port ,polished to the extreme of getting into the pushrod area which they epoxied, previous owned=they. We will get that fixed for road durability. Am I on the right track? Any suggestions?