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Old 07-14-2010, 10:04 AM
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backyard 327..questions???

ok guys i have a 72 350 block two bolt main ..std.piston and i have used a forgered 327 crank new mains and rod bearings .. im using 350 heads with 1.72/1.50 valves yea i know they are small but thats what i have ...a pj gear drive elebrock rpm intake and 650 carb gonna stuff it into a s10 whatcha think ? also was thinking of adding roller tiped rockers whatcha yall think ?
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Old 07-14-2010, 10:23 AM
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Is the 327 crank a large journal or a small journal? Large journal forged 327 cranks are very hard to find being they were made in very limited numbers in the last 2 production years of 1968 and 1969. If you have a small journal crank you can get spacers so it`ll bolt in the 350 block. I would still get rid of the heads. with 1.72 valves the power band is over at 3500 RPM.
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Old 07-14-2010, 01:00 PM
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Back in the day there was a lot of controversy over 327 vs 350. Many a gearhead swore up and down that the smaller 327 was superior and they based this on 327's winning races over the 350. Not only have I seen this phenomena, but Ive done it. I had an old 64 with a basicaly stock 327 (172/150 valves) and a small carter 4 bbl that would smoke a stock 350. True story, but this had nothing to do with mystic powers and everything to do with heads. The thing that killed a lot of early 350's was large compression chambers. Put the same large chambered heads on a 327 and the bad effect will be even worse. Yes, compression is that important.

It is possible to get a set of 172/150 heads to run very well on a 327, but what size are your chambers? If they are large chambers then you might as well keep a V-6 in that s-10. BUT, get the compression right on a 327 and you can do things to increase airflow, like some porting for the cost of a few tools and some time and get a little more cam lift. Make sure you get the compression ratio right though and your torque peak will be VERY respectable for a short stroked small block.

I like 327's because they deliver a lot of bang for the buck, it is possible a to strike a nice ballance with them between decent power and economy. In an S-10 you'll have a real screamer if you cross your t's and dot your i's.
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Old 07-14-2010, 01:12 PM
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Also, Im putting roller tipped rockers on my 327, but if you are working with a tight budget then a good cam will cost less and deliver more.

I opted for an Elgin E-1029p. Very similar to the old l-79 350 horse cam for about $40.00. Good roller rockers will cost considerably more and provide far less results. Especialy considering your small valves. Extra lift is almost a direct substitute for valve diameter.
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Old 07-14-2010, 02:39 PM
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Good info from both members, I also wouldn't even think of using those heads on ANY performance build no matter if thats what you have. The rest of your parts and build will be absolutely worthless, a waste of time and money if you use them.

Get rid of them, save your money and buy a set of 1.94 heads...even if they are stock chevy heads. Do some pocket port and gasket match work on them and a good 3 angle valve job.....she can't run if she can't breath.
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Old 07-16-2010, 01:28 PM
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its a large journal forged crank my dad found it for me ...
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Old 07-16-2010, 01:32 PM
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and they are big 76cc heads with the small valves so if i use these heads i should bump up to the 1.6 rocker arms?
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Old 07-16-2010, 02:30 PM
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personally i think 327 are ju
nk i built one it had fuely heads 450 lift cam i went thru this motor completly and took it to the track i had 350s out runnin me it was small journal by the way
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Old 07-18-2010, 03:25 PM
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Quote:
Originally Posted by ironhed103
and they are big 76cc heads with the small valves so if i use these heads i should bump up to the 1.6 rocker arms?

A 327 with 76cc heads. That is a horrible combination. Your building a guttless wonder. At the very least spend $50.00 and get a set of 305 heads from a junkyard or something. You are looking at some very low compression, a stock 283 would have more power.

Get a better set of heads, the ones you have are best used for boat anchors. If you forget all other add-ons and do nothing more than add a good set of heads you will be ahead in horsepower. Otherwise you can add things like rockers, intake, exhaust or whatever and none of it will matter because your building on a weak foundation.

Last edited by 65smallblock; 07-18-2010 at 03:41 PM.
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Old 07-18-2010, 03:37 PM
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Quote:
Originally Posted by chevy238
personally i think 327 are ju
nk i built one it had fuely heads 450 lift cam i went thru this motor completly and took it to the track i had 350s out runnin me it was small journal by the way
327's can compete with 350's all day long, but they are more finicky. They need to be set up right. If you have a heavy car and the wrong gears it wont do well. 350's are more versatile that way because they run in a lower power band.
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Old 07-18-2010, 07:09 PM
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If 2 sbc are built the same way (heads, cam, compression, ect) then the bigger engine will make more power every time.

power is all in the heads, all the block needs to do is hold together.

those stock 172/150 heads will max out at 300 hp no matter how big the engine is or what cam you use. The general rule of thumb is you need 200 cfm's to make 400 hp. And that would take a healthy cam, intake, and exhaust system to get 400hp out of a 200cfm intake port.

So, use the biggest engine you can and use the best set of heads you can afford. Install at least a 350 crank in that 350 block and get a set 1.94 heads. set compression up to match the cam, gear, and stall. It all needs to match.

nothing wrong with cast pistons or cast cranks up to 400hp.
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Old 07-19-2010, 09:33 AM
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Quote:
Originally Posted by 454C10
.

those stock 172/150 heads will max out at 300 hp no matter how big the engine is or what cam you use. .

They may "max out" @ 300 hp, but if those old 350 low compression heads are used on a 327 he will never even get close to 300 hp!! no matter what cam or ?? is used. It is a lousy combination to start with. Your right, the parts need to match..
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Old 07-20-2010, 12:50 AM
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Ok...

The 327 would work, but you need to change a couple things.

1. Scrap the heads. Find some 67cc heads, with 1.96 intake valves. Don't worry about getting the 2.02 valves, they don't help much under 5500. Get some steel shim head gaskets, to get a bit more compression. Use lots of copper-spray-a-gasket on them, at least one can on the pair, to make sure they seal.

2. Forget the gear drive, and get a good cam/lifters/pushrods instead. I would suggest higher lift, .490+, to take advantage of where the 327 will make power. A regular double roller timing chain will be great, and a bunch cheaper.

3. Roller tip rockers are fancy, but get some standard rockers if your strict with your budget. Take the money you save and get a good set of headers, 1 5/8 size.

4. Get a weiand 7547 intake, or a edelbrock torker 2 instead. Single plane, better for where the 327 makes power.

5. 650 carb should work, but a rebuilt q-jet will flow more, and gives better throttle response imo.

6. Get a good ign module, coil, and plugs/wires, 327's love rpm, you'll need a good ign system.

Just my opinion, but this should make one hot 327, and should really scream!! Especially in a light vehicle.
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