Small Block & Big Block Chevy Specific - Need expert engine advice for 327 build
yungone501
06-26-2006, 12:04 AM
I am currently building a large journal 327 2-bolt main engine for my s10 v8 conversion and need an experts opinion about the performance capabilities of my configuration. The short block consist of all forged components: crank, rods and pistons. Pistons are .040" over flat-tops handing out 10.5:1 compression. Rotating assembly has been computer balanced and should be receiving the block here within the next week or so. On top sit a pair of Dart Iron Eagle 200cc intake runner, 59cc, 2.05/1.60 heads that have been pocket ported, shrouded valves and polished combustion chambers. Estimated flow would be around 275cfm's (262 stock). The brain is a flat-tappet solid cam boasting specs as: I/.531 E/542, 248 @ .050 duration and a 106* lobe seperation. Of course it has roller rockers (1.5's). I really wanted to go all out on this project but fear might have gone "too" far. I love high RPM small blocks but would like everyone's( preferably the experts) opinion on this setup. Let me know what you think. Thanks ya'll! :)
Oh yea, one more thing. Also using the Victor Jr. intake along with a Speed Demon 800cfm carb. Sorry.
NemeSS
06-26-2006, 02:18 PM
with the size of that cam, how come u just didnt go with a solid tappet?
seems like u have the heads
are u looking to turn 7k+ rpm?
johnjzjz
06-26-2006, 05:00 PM
is it a street car or bracket car heads are on the large side with that cam the 106 is for a racing CL a 104 intake would have more bottom for the street 59 cc 327 yea 10. to one if its street and you cant stop it from pinging take off heads and use a .060 thick gasket sometimes a full cyn dist with strong springs and a 34 to 36 max advance if its a race car 40 or more might help if its a 2 speed to cut better light or going in deep ( stagging ) my take jz
yungone501
06-26-2006, 09:09 PM
To the first response: The cam is solid. Im aiming for 7-8k RPM range but not sure about this cam now. Ive plugged some other cam numbers into DesktopDyno and came up with some pretty luring HP ratings. Even with a smaller duration cam and lift, Ive managed to find larger HP's at even less RPM's...what gives?
And to the second response: This is a 75% strip/ 25% street truck. You say I should go with a lower LSA but according do the pro's, that will decrease my HP. However, thicker head gaskets might be better. I really think I should go a different route with the cam...
LS199CAMAROZ28
06-26-2006, 09:50 PM
i would definately not go by what the desktop dyno says. call comp cams and tell them what you are looking for, that will always be the best bet. why so many rpm's? 8k rpm's on a 2 bolt main is alot! what kind of times u looking for?
yungone501
06-27-2006, 10:05 AM
Yes, I know, Ive heard similar responses about DesktopDyno. But its better than guessing right, LOL. You ask why so many RPM's, well, Im one of those high RPM v8 freaks! We're few and far between but I absolutely love the sound of a screaming small block. And I know for a two bolt main thats asking alot but Ive gotta spare small journal 283 with forged internals just sitting aside if the 327 expires early. Its all about having fun with it! Im looking to get this s10 to atleast 10's. And yea, I know, I could get more HP out of more cubes but thats not my style and bigger cubes are too mainstream.
NemeSS
06-27-2006, 03:48 PM
To the first response: The cam is solid. Im aiming for 7-8k RPM range but not sure about this cam now. Ive plugged some other cam numbers into DesktopDyno and came up with some pretty luring HP ratings. Even with a smaller duration cam and lift, Ive managed to find larger HP's at even less RPM's...what gives?
And to the second response: This is a 75% strip/ 25% street truck. You say I should go with a lower LSA but according do the pro's, that will decrease my HP. However, thicker head gaskets might be better. I really think I should go a different route with the cam...
the difference could relate to superior valve events on those other cams u plugged in affecting the DCR and other valve events ,compared to the one u have now,
dont resort to thicker head gaskets,manupilate your DCR with valve events and go with as much as SCR that will allow the use of pump gas,and appropiate timing for both street and track, pinging or knock should not take place if u make a few calculations and have proper quench
go with a cam that will maximize your heads thru out the power band
yungone501
06-27-2006, 08:11 PM
Do you really think my compression ratio is affected that much just by a simple cam swap? In some instances, HP numbers jumped or dropped as much as 50HP. Generally speaking, one point of compression usually equals 20 or more horsepower. How does the cam manipulate compression? By keeping a valve closed on the compression stroke a little longer than normal? If there's one thing I lack knowledge in, its how different camshaft characteristics operate in a running engine!
johnjzjz
06-27-2006, 08:12 PM
the difference could relate to superior valve events on those other cams u plugged in affecting the DCR and other valve events ,compared to the one u have now,
dont resort to thicker head gaskets,manupilate your DCR with valve events and go with as much as SCR that will allow the use of pump gas,and appropiate timing for both street and track, pinging or knock should not take place if u make a few calculations and have proper quench
go with a cam that will maximize your heads thru out the power band
Last year i would agree ( todays fuel at the pump ) but he said his static is 10-1/2 that was the reason thicker gaskets Stop the ping ????? ( first no )longer duration will only work up to a point its a street car as i see it jz