Thread: 327 build opinions

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hey everyone, iv put together my first engine did alittle research here and there but deff. not enough but here is what i have on my hands tell me how i did. please be nice
afr 180cc 64cc combustion chamber
5cc valve reliefs
comp magnum 292h cam .501 lift hyd. lifter (wondering about this)
1.6 roller rockers
edlebrock torker intake
650cfm carb
This engine is going in a back in a fiero so the car does not weigh all that much and has rather low gearing, so max tq is not a huge concern. it will also just be a weekend street car with a few trips to the track.

edit: just looking at #s and i see that this is most likley not a 327 with a cast # of 3970010 and with the 4 bolt mains this narrows it down to either a dz302 or a 350. the guy i bought it from is a experienced engine builder and iv heard rumor of 4 bolt 327 comming out of industrial trucks and he did mention truck block, if i remember correctly. so im not counting the 327 out completely. im goin to look for the dz code in the morning.
considering this what type of power increase could be expected from a 327vs 350.

Cannot seem to see a magnum 282 H in the competition catalogue, but I do see a 292H with .501 lift. Got the part number handy.

But first you want to understand the differences in static and dynamic compression ratios. Camshafts have a lot of influence on dynamic compresion ratio.

Here are 2 links.... the first one explains dynamic compresion ratio.

http://www.empirenet.com/pkelley2/DynamicCR.html


This is a dynamic compresion ratio calculator


http://kb-silvolite.com/calc.php?action=comp

You have a 327 with 64cc heads it will be a pretty good bet that your engine is around or close to 10/1 static compression ratio

Go to the lunati cams site:


http://www.holley.com/data/Products/Technical/20109.pdf

this gives you the camshaft timing card. Now as to the text this will give you the time when the intake valve closes in degres plus 15 that you will add. This is Lunatis copy of the Duntov 30 30 solid cam.

Choose some other cam cards from your favourite grinder and this will give you a good working knowledge on cam selection on what you can and cannot run in your motor.

I think if the guy knew it was a 302 he would have wanted a lot of money for it. The build looks pretty good to me, AFR heads run good with single pattern cams so you did good on that part. The cam should be alright on a 350, but you actually don't need that big of cam with AFR's. They flow very good and you want to watch how much overlap you put in the cam on smaller engines. If it is a 327 you should find a cam with less overlap. You don't want too much. As for compression, I believe the cam you have recommends 10.5 to 1. You have around 10 to 1? So the smaller 280H might be a better cam for you. 1.6 roller rockers also adds more overlap, so you may want to consider 1.5's.

i see that this is most likley not a 327 with a cast # of 3970010

What is the 2 letter suffix, passenger side, front, just below the head?
Flat stamp plate looking up at you.

http://www.nastyz28.com/chevy-engine...ngs.php#suffix

thanx for all the help guys im feeling better about this engine now. also i scraped the paint and there are no numbers on the block under the head. and im getting a good understanding of dynamic compression.
and now i must ask assuming this engine is a 327 whats a ballpark of hp. and tq? 400hp and 380tq maybe?

Now do you understand that to run a certain cam of your choice that you can enginer the motor to get a perfect dynamic compression ratio of 8.25 / 1 on the street running gas. One way is to surface the block to close up the piston to head clearance, another way is to use different head gasket thicknesses. Or you can use domed or dihed pistons, though this is frowned on because it affects squish.

Posted by southerner:
"Or you can use domed or dished pistons, though this is frowned on because it affects squish."

Good point southerner. If you are going to use dished pistons, use ones that have the dish offset to the chamber side of the piston so you have a nice flat surface on the piston crown to interface with the underside of the head. I would advise against using domed pistons in anything but a dedicated race motor where you have fire slots in the dome. The dome gets in the way of the flame front as it travels across the chamber. Use heads with the correct chamber size and juggle the piston deck height and gasket thickness to fine tune the target static c.r. and squish. I'd much rather use a small chamber and flat-tops or an offset dish than a larger chamber and domes.

ok im trying to figure out my DCR but cant figure out what my intake closing point is at ABDC @ .050 is becous on my cam card it is listed at .006 can someone help me out with this it is listed now as closed @ 74 ABDC
thanx for your help so far