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Post by rayray4all on Nov 29, 2004 7:59:18 GMT -5
How can I determine history/size on Motor block and heads? The number of the motor is 397000 The # on the heads is 3870128 If someone can lead me in the right direction would be very thankful. Maybe a web-site?
Changing the old 305 with 350
Thanks
Ray
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Post by Bent on Nov 29, 2004 17:41:45 GMT -5
www.mortec.com [glow=white,2,300]Has alot of engine and head casting numbers listed. YOu might try and look closer at your numbers, as they are not listed and I noticed that your engine code is missing a number ;D[/glow]
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Post by 19_Chevelle_69 on Nov 29, 2004 19:00:52 GMT -5
The engine number is likely 3970010.
3970010....302.....69....4...Z-28 Camaro 3970010....327.....69....2...Trucks and industrial 3970010....350...69-80...2 or 4bbl
Also, if you can get the numbers from the pad on the front of the engine block at the end of the pass side head (under the alternator), I could probably narrow it all the way down to a HP rating for you as well.
That exact cylinder head casting number isn't listed, but here's a close attempt at a match...these old casting numbers can be tricky to read sometimes.
3970126....67-71...327/350
Do you know what year/application this engine is from?
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Post by rayray4all on Nov 30, 2004 11:45:03 GMT -5
I took a closer look at the numbers and the correct number for the block is 3970010. The heads numberis 3970126. Thanks for the help! Looks like its eather a 327-350? 67-70 Located the number below the alt. V0903TXB or is it the one that looks like a serial #?
What is alternitive for determining if I have 327 or 350? Lenght of stroke? diameter of cylinder?
Thanks Ray
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Post by 19_Chevelle_69 on Nov 30, 2004 13:14:55 GMT -5
You need to look no farther than here.... YEAR - 1975 SUFFIX - TXB DISPLACEMENT - 350 VIN DESIGNATION - L RPO CODE - LS9 HORSEPOWER - 165 CARB - 4BBL APPLICATION - C-20 to 3500 conv.cab Some more misc info for you.... V - 09 - 03 Built in Flint, MI (V) Sept (09) 3rd day (03) And there you have it....another smallblock ID'd.
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Post by rayray4all on Nov 30, 2004 15:12:50 GMT -5
Thanks everyone for you much needed help!
Ray
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Post by 19_Chevelle_69 on Dec 1, 2004 19:27:20 GMT -5
No problem, glad to help out .
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Post by BowtieGuy on Dec 2, 2004 9:04:25 GMT -5
Now there is a man that knows his numbers. And he wonders why I like having him around. Great work Don. Don't know what we would do with out you. :bow:
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Post by rayray4all on Dec 2, 2004 9:14:06 GMT -5
Now I know I have a 70 - 350, 165 hp
Looking at the heads discription as: 3970126....67-70...327/350 What does this mean? Stock? Just trying to understand the cc chamber sizes.
Next - the two center valves are litght tan and the outside valves look to have more a black tent. Is this normal?
Ray
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Post by 19_Chevelle_69 on Dec 2, 2004 17:49:28 GMT -5
Your engine is a 1975, not a '70....
OK, so the heads are your run-of-the-mill 76cc chambers, and most likely 1.94/1.50 valves.
Not a performance head by any stretch of the imagination, but still better than some of the newer 1.85/1.50 ones... :nono:
Oh, the number you saw that looked like a VIN? It IS a VIN...lol. It's a partial VIN from the truck that got that engine at the factory. They engines were stamped before they were installed into the vehicle. It is where "numbers matching engine" term comes from.
The main reason for the lighter color center valves is due to the extra heat that comes from the exhaust crossover passage under the intake manifold. It's there to help EFE, and to heat up the divorced choke style choke spring in the days before electric choke heaters..... It's normal.
Bowtieguy..... You know me well. Numbers are just my thing....LOL
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Post by rayray4all on Dec 3, 2004 8:41:26 GMT -5
Thanks Don for the correction on yr. Need alittle more help! How do these heads differ than the ones Bowtie explained in the thread "Making more HP cheap".
Cost? If the heads I have need a rebuild, what will the cost for the build vs the remfg. head be?( estamated only)
Ray
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Post by 19_Chevelle_69 on Dec 3, 2004 16:25:02 GMT -5
The heads you have use the 76cc combustion chamber, which are low compression/standard heads. Yours also have the 1.94" intake valves, and 1.5" exhaust valves.
The ones BTG described use larger valves (2.02"/1.60"), and have 64cc chambers which bump the compression ratio up. Also, the larger valves flow better. (No brainer there...LOL)
A VERY quick SCR calculation shows that your engine with the current heads, and a common aftermarket head gasket will be at about 8.1:1 SCR. If you were to bolt on a set of 186 heads with the 64cc chambers, it would bump up to 9.1:1 SCR.
Along with the power increase from the higher compression, your engine would also benefit from the better flowing valves. And with your factory dished pistons, your SCR of 9.1 won't require you to run high octane fuel to prevent pinging.
As far as price goes, it would be hard for me to tell you as the market prices vary from place to place. Also, I can't say how much "rebuilding" your current heads need.
Give your local machine shop a call. Ask them how much to completely redo a pair of heads, COMPLETLY. Valves, guides, seats, the works, and compare that to the price of buying a pair over the counter. When you get a quote from the machine shop, you have to remember that you have a quote for a REAL rebuild. When you buy heads over the counter, they usually get a "Fix-only-what-it-needs" rebuild.
If you don't know your local machine shop, call your GM dealer to see who they use for their machine shop sublets...
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Post by baseface on Oct 13, 2007 3:55:15 GMT -5
I just joined this site, It's great!! I have a similiar issue with my new 350. A friend just gave me an '81 window van with a crate 350 with basically no miles. The body went so he gave me the van so I could swap the engine from my '87 GMC 305 4x4. I'm trying to find out the HP of the engine he gave me. The serial number on the block is 3970010, and it has a 4bl carb. I guess I am to understand that the engine is putting out 165 HP? That would mean it's not a 4 bolt main I take it ah? I thought I might have lucked into a high powered engine but no such luck I guess. I went to some sites to find out what info I could get on the engine. They all said it either had 165 or 370 HP, and either a 2 or 4 bolt main. We haven't taken the engine out yet, I was thinking if it were a big power plant, I'd put it in another vehicle. Maby someone could give me a little more info. Thanks Guys
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Post by BowtieGuy on Oct 13, 2007 16:38:42 GMT -5
Unfortunately the numbers for the engines are not real specific. The numbers for the engine you have is 69-79 year 185-370 hp engines either 2 or 4 bolt mains so no more help can be offered by that. Sorry we can't help more.
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