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Just stripped down 327/340 out of my 63. Mechanic says to use hydraulic lifters instead of solids. He says will make car easier to maintain without loss of performance/value. This is original engine in a solid #2 car. Any thoughts on this change or other changes, such as lowering compression to 9.5. Thanks!
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Re: 327/340 rebuild
If it was mine, and it isn't, I would install flat top cast pistons and a 327/350 hyd cam. -
Re: 327/340 rebuild
I like what Ed just said. The mechanic is correct about the ease of maintenence etc. If you drive it more often than store it, you have a pretty good case for the cam change at this point. Dale's Favourite "151" cam, advanced 4 degrees (actualy check it) with Rhodes variable duration "cliking" style lifters seem to be an excelent choice for this application. Run about 9.5-10:1 C/R. You still get the solid lifter sound as a bonus. Lots of power/torque and appears to be stock. Since it is a #2 car, you need to keep the mods down to a minimum and this setup will not be difficult to change back if the next owner wants a concours original spec engine. Ordinarily I like totaly stock original, but for something driven, this is how I would go. I wish I had your choice to make.
-Mark.Comment
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Re: 327/340 rebuild
Pete:
It depends on what you want to do with the car. If you want to drive it, then stay around 9.5-1 or 10.0-1. Flat-tops should give you that depending on the heads. That should let you use pump premium without additives and the hassle there provided you do not have 64cc heads in which case your compression should be around 10.25-1 assuming the heads have not been cut. That can be livable though. Anything above that and you are going to have to go to mixing additive or AV gas to boost your octane. I had the domed pistons fly cut for my 70 454 to 9.75-1 and it runs great! Beats the pants off most other cars but I can run on pump premium.
I love hydraulic cams - set em up once and forget about them. There is alot of conversation about cams on the board -- check archives. But I picked the L-82 hydraulic for my 350. I haven't got it running just yet (you can read the reasons why)-- but Duke, Jack Humphrey, John Hinckley and Joe Lucia all advised me that this was a great street cam -- good torque and HP through the power curve. You might consider that.
The machinist is telling you honest truth about drivability and supportibility in my estimation. While I like solid lifter engines (nothing quite like the sound), they can be a real PITA to maintain with adjustments and the such. It comes down to do you want to piddle with the motor and adjust the valve lash, or do you want to fix it once, and then just drive it maintenance free in 2002. Only you can make the decision. Both rebuilds will work.
Hope this helps --
PatComment
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Comments and follow-up questions
Jeez, you'd think checking the valve lash every 15K miles is some kind of major operation. It's not! Takes maybe a couple of hours going slow and easy - enjoying the experience of tuning a Special High Performance engine. It's a ritual for me.
If you have a fairly original car, keep it that way by continuing with mechanical lifters, but replace the original Duntov with the 70-72 LT-1 mechanical lifter cam. It's available from Federal Mogul Performance Parts, and instruct your engine builder how to properly adjust the valves (check archives). Most do it wrong! If they're done properly the adjustment will last.
You can buy replacements for the original forged pistons from FMPP also, and they should be fit at .0035" skirt clearance. Using a modern composition gasket, about .040" thick will put the CR at about 10.5, and because of all the valve overlap it should run without significant detonation, but you might have to run a bit of high octane leaded or unleaded race gas mixed with pump premium, or juggle the timing curve a bit.
You could also have the modest 1/8" domes cut off the pistons for about a quarter point drop in CR
Did it run without detonation on unleaded pump premium before you disassembled it? Also, did it have two steel shim head gaskets per side?
If you want a stronger top end have the heads pocket ported and port matched with a three angle valve job, but keep the original 1.94"/1.5" valves. Hogging them out to 2.02/1.6 will increase the 461 head's tendency to develop a crack between the two valves.
DukeComment
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PS
Early small bearing rods are prone to cracking near the bolt seat and many have broken over the years. The later small bearing rods have a bit more material around the bolt seat and are much better.
Magnafluxing early rods is MANDATORY IMO, but rather than waste money on them, just buy a new set of rods. The Crower Sportsman are bullet proof out of the box and are sold in balanced sets of eight.
Also, DO NOT ALLOW ANYONE TO TURN THE CRANK. This will remove the surface
hardening treatment and weaken the crank. Check all the journals (they are likely still in spec) and have the crank checked for staightness. Beyond a journal polish it is likely perfect and will last a million miles as long as it's not oil starved.
Be very careful of who and how you have this engine rebuilt so as to preserve the excellent engineering and materials that went into it (exept the rods).
A lot of guys talk about "modernizing" these engines, but IMO you can't beat the quality of the vintage specification parts, and most are still available from FMPP.
DukeComment
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Re: Comments and follow-up questions
Duke -
I do not disagree with you. There are just less and less of us out there who just love to piddle (and have the knowledge) with an engine. I would tell most guys to put the tri-pack in a box and put a 4BBL manifold/carb on too unless they like tuning and fiddling with Holley carbs.
Its all a matter of INFORMED choice. But better they know they will have to do that then thinking "ooooooohhhhhh solid lifter cam -- what a thrill" not knowing they will have to pull those valve covers to adjust the lash and rarely get the performance they should out of the engine.
I think it has to do with my wife and kids -- I think she is going to divorce me if I don't finish the 73 :-)
PatComment
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Re: 327/340 rebuild
Peter-----
For a 327 340 hp a swap to the '151' camshaft and hydraulic lifters might be a very good choice. In doing so, you're essentially converting your engine to the L-79 configuration. The only differences will be the fact that you have the 1.94/1.50" valve size instead of the L-79s 2.02/1.60" valve size and you have a Carter AFB rather than the Holley used on L-79s. Neither of these factors will have much negative effect on achieving L-79 performance.
What you'll end up with is an engine with idle and power/torque characteristics similar to what you have now, but you won't have the problems associated with a mechanical lifter camshaft. That's why after 1965 the L-79 supplanted the earlier mechanical lifter engines.
With respect to the choice between the L-79s GM #3863151 camshaft and the L-46/L-82s GM #3896962 camshaft, I consider that the '151' is the best choice for 283-327 cid engines and the '962' the best choice for 350 or larger cid engines.
If you are currently having no detonation problems running your engine's 11.25:1 compression ratio with pump gas, then you should have no trouble with the conversion to the '151'. To be safe, though, if you're replacing pistons, I'd reduce the compression ratio to about 10:1 which will be achieved if you switch to flat-top, 4 "eye-brow" pistons.
Just to be clear here, though, my recommendation is based up conversion of your engine from a 340 hp. For conversion/upgrade of a 300 hp in which the maintenence of stock idle and vacuum levels are a priority, I'd still recommend going to the 260 degree-type cams.In Appreciation of John HinckleyComment
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PS Addendum
A lot of engine shops are like "turn the rotors" brake shops.
They just deck the block, mill the heads, and turn the crank apriori.
If this is the kind of guy you are dealing with run like hell.
A good shop will measure these parts and not do any machining unless absolutely necessary. Contrary to popular myth, the decks are usually quite parallel and rarely need to be surfaced. They may be a bit high, but this will keep you CR down. Go to a shop that has the proper tools to actually measure the crankshaft centerline to deck dimension on all cylinders. If it is out of parallel it can be machined without destroying the stamped pad.
Same applies to heads. It's easy to measure for warpage, and they should not be cut unless warpage is significant. A composition gasket will easily handle a few thou of warpage.
Develop a plan with your rebuilder to make all the proper measurements and only remove material if you both agree it's necessary.
Other than the cam and rods use all OEM or equivalent parts, and if you do the port matching/pocket porting and a three angle valve job you will have one killer SHP engine that will last through countless runs to the redline.
Duke
DukeComment
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Re: 327/340 rebuild
This might seem to be a small point but when the general used the L-82 cam, he also used screw in studs and guideplates. The ramps on the L-82 cam are faster than the "151" cam and while that is good for torque/power production, the faster ramps add load to the valvetrain. It might be good insurance to follow the generals lead when using the L-82 cam and upgrade the valvetrain to L-82 specs when that cam is used. They didn't just give them away because they looked cool with the valve covers off.
-Mark.Comment
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Re: PS Addendum
Duke makes reference to decking the block. Just as a side note...if your machine shop does have to deck the block you may want to document (photos, video, tracings, etc..) the numbers that are on the pad prior to decking.
MikeComment
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Re: 327/340 rebuild
I had my 62 vette, 327/ 340 hp engine built by Classic Engine Company. I have solid lifters and 10.5 forged pistons.Comment
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Re: PS Addendum
I would seek out a machine shop willing to deck the block without cutting the stamp pad....it can be done!....I know Serdi makes a decking machine that allows this, and I have also read the more common Storm-Vulcan rotary machines can do this if the operator knows how to set up and position the block so the cutters don't hit the stamp pad. Mostly, it is shops not willing to try, bother, or experiment.....CraigComment
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