strotter Posted January 4, 2002 Share Posted January 4, 2002 I'm just beginning the final assembly of a 327 for a Z conversion. Looking closely (apparently for the first time!) at the .202 double-hump heads, I noticed that the walls that divide the intake ports (both front and rear) have been worked to the point that they're thinner than the standard Fel-Pro manifold gasket. As a matter of fact, they're about 1/16th of an inch! The gasket measures a little less than 1/4". Seems like a recipe for vacuum leaks. I'm open for input here. I'd hate to trash the heads - somebody obviously put a great deal of work into them. Any suggestions? Metallic gaskets (are they available for intakes?) or modifying a conventional gasket? Another question about this engine - easily fixable, but strange. After I noticed the head problem, I looked the whole thing over carefully from top to bottom, and found another odd thing: there's no hole at the front of the crankshaft for the big bolt on the front that holds on the harmonic balancer and pulley assembly. It's not that the hole is stripped, or drilled out, it just isn't there! A balancer and pulley were on the front, and I missed it because I had just assumed that there wasn't a bolt there. Odd! What kind of crank has nothing to hold the pulley on? All I can think of is that it was a "blank" of some kind, available for speed shops to do custom work on - it has been balanced to within an inch of its' life. Or maybe a marine unit? Hmmm? One of the local machine shops is going to drill and tap it for me, cheaply and easily, but it seemed odd even to them when I talked to them on the 'phone yesterday. Any ideas? Finally, the problem with the double-humps got me to thinking about Vortecs. Ooooh, they're affordable, they're new, and they flow like the Mississippi. The 327 uses the same bore as the 350, so they'd fit just pretty, and I might even factor in a compression bump (with the flat-tops and the 62cc double-humps I've got about 9.75:1. I could bump that to about 10, 10.25:1, which might work better with my set-up). A compression calculator I found tells me I'd need a 58cc chamber to get 10.24:1 (with a deck height of .039" and a gasket thickness of .025). I havn't settled on a manifold yet, so I don't mind a vortec-only unit. Just have the machine shop take a bit off the bottom (how much is yet to be determined) and have fun. Comments? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2002 Share Posted January 4, 2002 well the old small blocks dont have a hole drilled out in the crank snout...if i remember its the 67 and older cranks.....which means the crank you have would be a small journal (hope im remembering this right)....as far as the heads, if you have the cash i would get the vortec..if not, finish the assy. and see if you get any leaks well later Quote Link to comment Share on other sites More sharing options...
383 240z Posted January 5, 2002 Share Posted January 5, 2002 My 65 327 does not have a crank bolt and is a small journal hope this helps Keith Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted January 5, 2002 Share Posted January 5, 2002 Ok, I'll bite. How'd they hold the pulley on? Quote Link to comment Share on other sites More sharing options...
Guest gbvol54 Posted January 5, 2002 Share Posted January 5, 2002 I just bought a set of Vortecs. Be aware the stock springs are good to 'only'.450-.480 lift(depending on the source of the information) and lift over that may require the guides to be cut. I'd like to keep the heads stock for budget reasons but can't decide on cam selection. I'm considering a single pattern Crane (#287 H10, Dur @.050 .222, LOA 110 and lift .467) or a dual pattern Comp (12-238-2, Dur 218/224 @ .050, lift of .462/469). Also debating the value of a Performer RPM Air Gap over the base Performer intakes. Looking for around 350 HP, running about 10-1 compression with a Quadrajet in a near daily driver. Grumpyvette has given me a lot of good advice and I've done a fair amount of homework (Lingenfelter and Visard's books plus tons of web sites)but am still having trouble pulling the trigger on a choice. Opinions? Quote Link to comment Share on other sites More sharing options...
strotter Posted January 5, 2002 Author Share Posted January 5, 2002 Gary, I've been doing the same research you have. I just picked up an LT1 cam (.447/.459 @ .050, 205°/207°, 117°) as an "starter" cam (to get everything running, set up the new roller lifters, get the fuel injection operational and tuned and whatnot with a proven cam). I've understand that performance from them is respectable, and they respond moderately well to mods. Seems like one might be ideal to use with a set of Vortecs. And, they really *are* available for 30-50 bucks, all over the place. Check http://www.thirdgen.org/ or http://www.chevytalk.com/ or http://www.lt1tech.com/. Quote Link to comment Share on other sites More sharing options...
Guest gbvol54 Posted January 5, 2002 Share Posted January 5, 2002 Thanks Scott for the quick response. What roller lifters did you go with? Again, cost vs performance? Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 5, 2002 Share Posted January 5, 2002 I`ll bite too. how do they hold the balancer on?-------------------DENNY Quote Link to comment Share on other sites More sharing options...
strotter Posted January 5, 2002 Author Share Posted January 5, 2002 Gary, I got one of the "K-kits" from Comp cams. It's what they call a "retro" kit, and includes everything in the valvetrain from the cam all the way out to the springs, *but* for the rockers. It's a fairly radical cam, especially with the TBI system I'm using (.495/.502, 218°/224° @.050, 110° sep), which is why I got the LT1 to start with - fewer variables to worry about. No matter which way I'll be going (double-hump or Vortec, though I'm leaning to Vortec) I can use it all. Vortecs need self-centering rockers, which adds to the cost unless you have to buy some anyway (which I *do*!) On my 327, they'll yield about 9.5:1 (which I guess is OK) without milling, and will work with the LT1 cam without valve guide mods. Think of it as a "Stage 1" buildup; when I get everything going smoothly with this setup, I can order the chip/machine the heads/replace the cam/install 2" TBI, and so on. My ultimate goal is about 327 hp (1 hp/cu in, doable and streetable with reasonable street manners and economy), but if I get 250 hp or so out of the current setup I'll be happy as a duck. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted January 5, 2002 Share Posted January 5, 2002 Did someone mention the harmonic dampener yet? That is, how the heck do they hold it on with no bolt? Grumpy? Pete? Anyone? Davy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 6, 2002 Share Posted January 6, 2002 It is held on by a compression fit. A bolt was not needed. It worked from 55 to 67. Quote Link to comment Share on other sites More sharing options...
fl327 Posted January 6, 2002 Share Posted January 6, 2002 hey, i thought i was missing my crank bolt too!! this is after two years of driving this car when i finally looked, now i feel good. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 6, 2002 Share Posted January 6, 2002 Hi all,I've been reading this board for a month or so,but never even registered till today.I'm in the beginning stages of a 406ci 280.The paper thin distance between the intake ports on the double humps caught my attention.Ten years ago I built a pretty bad ass VW bug (12.98/100.2mph).I was running dual 48 ida webers on a pair of heads that had been welded on and ported so much that the intake ports were bigger than the O.D.of the stock gasket and very thin.The only time I ever lost an aftermarket gasket was on a very hard downshift(like 7500rpm).I dont think it would be a big deal if its thin only between the two ports.Yes it would run bad if it blew,but it would'nt run lean and blow torch a piston.And there is really no manifold vacuam as long as you keep your foot on the gas.right? Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 8, 2002 Share Posted January 8, 2002 Sorry, I've been in the garage - working on my shortblock and then my double hump heads (cleaning the porting job up a bit, lapping valves/seats, a bit of chamber cleanup). I've done a half doezen 327s and they ALL were pree 1968 and ALL had the snout drilled and tapped - could have been from the factory or after the fact, I'll never know. Yes, some were not also and a press fit was used. But I surely would prefer a bolt! 1/16" between the ports does sound a bit thin. I'd trim the gasket, but a mismatch here isn't so bad, from what I've read. I'd want a good gasket preferable with a metal core also, but probably not mandatory. Search around the aftermarket for a metal/composition gasket, I think they're available. Quote Link to comment Share on other sites More sharing options...
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