Guest tom sixbey Posted July 18, 2001 Share Posted July 18, 2001 gotta question... - can you destroke a 350 to produce a 327? what would be the way to go about doing it? - i cant seem to find any kits for it, but i heard somewhere that they are out there... Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 18, 2001 Share Posted July 18, 2001 A 4"Bore SBC block would require a 3.25" stroke. The PAW book under [Crower Cranks] has a 3.250" crank...but their prices range from $1700-$2100. I dont know what the dynamics of having a standard crank off-center ground would yield or if it can even be done, but, maybe you might call a specialty shop & shoot the question; certainly its been done before. Either way-its gonna cost you if you are set on using a custom ground crank. Kevin (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Peternell Posted July 18, 2001 Share Posted July 18, 2001 Heck find a large journal 327 crank (1968 only?) and get a steel one to boot or get a 307 crank (all large journal) and balance the rotating assembly. The 307 crank (3.25 stroke) will work, but is balanced for lighter pistons. You can usually find a 327 LJ crank on E-Bay for $250 + shipping. Use a 350 4-bolt block and a 327LJ or 307 crank and then you could have a 4-bolt 327. Later Larry Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 18, 2001 Share Posted July 18, 2001 you can get four bolt main 327's but i think it would be a great idea to destroke the 350 into one, that may you have thicker cylinder walls, tougher i think. my buddy has a truck with a 383 that was really a destroked 400, and that mother hauled asses..... Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted July 18, 2001 Share Posted July 18, 2001 here's an idea - would it be possible to get a small jounal 327 crank and use spacer bearings to get it to fit the larger journals, or is that a bad idea for a performance motor? (all the destroked 377s use em...) in the meanwhile i'll look for that 68 327 crank! Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 18, 2001 Share Posted July 18, 2001 I've never heard any negatives on the spacer bearings, anyone else that has? Davy Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 18, 2001 Share Posted July 18, 2001 i dont like the idea of them at all, why do all that when you can just get a four bolt main 327, not that it would make much difference until you start making more than 500hp, are you? Quote Link to comment Share on other sites More sharing options...
Guest Night_rider_383 Posted July 18, 2001 Share Posted July 18, 2001 Fairlady327...Hey man where ya finding these 4 bolt 327's at bud. I would like to get one if the the price is right. I know its an after markt or machined blocks. right?. Is it the 2.30'' mains and 2.00'' rod or the 2.45'' mains and 2.10'' rods. As far as i know Gm never made a 4 bolt 327. I was talking to the machine shop i use in atlanta when i built my 327 about having the block machined for 4 bolt main and buying aftermarket caps and will the price he wanted to do that was just alot more than i wanted to pay so i left it 2 bolt. Quote Link to comment Share on other sites More sharing options...
Two40MuscleZ Posted July 18, 2001 Share Posted July 18, 2001 Original/early style 327's were only 2 bolt mains. The 4 bolt mains advertised use aftermarket splayed caps. Cost effective, your pocketbook,your call. As for durability...I have never had a problem. In talking with some of the old-time street racers, the concept was explained like this. 327/350hp short stroke, quicker revs. and practically bullet-proof. Great design and dependability. The 350 design was made out of necessity. Designed with a slightly longer stroke, lots of torque, and good overall response, however, there was a main bearing failure problem associated with them. Hence, the "workhorse" vehicles, i.e., trucks, were beefed up to the handle the excess torque and stress factor. The 327 line never experienced any mangitude of that problem. One other smalll contributing factor was; lack of sales! Thats right, the 327 engineering was right on the mark, thus never required the parts inventory associated with so many others. Basically, GM engineered themselves out of making money! Hence, the emergence of the 350. As solid as it maybe, it still has calculated engineering brakedown figured into it! Van Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted July 18, 2001 Share Posted July 18, 2001 i (erroniously) thought that the old 327 blocks were identical to the 350 blocks except in the main journals.. if i could destroke a big journal 350, it would be perfect. about the bearing spacers - I don't like the idea of them either. I guess it would be best to find the 307 (or 327 LJ)crank and forget all about em. fairlady327, i dont have any immediate plans for anything greater than 400 hi-RPM horses. I'm intrested in the 327s mainly for the powerband they tend to produce. (hopefully i can avoid some of that notorious tirespin!) [ July 18, 2001: Message edited by: tom sixbey ] Quote Link to comment Share on other sites More sharing options...
Mike C Posted July 18, 2001 Share Posted July 18, 2001 Hi, What a great board! I am new here but not to Z cars or small block chevys. The large journal 327 was made in 68 and 69 and was made from 68-72. Any of these can be carried over into some 70 models. These 307 or 327 cranks can used to build a large journal 4 bolt 327 using a 350 block as long as the assembly is correctly balanced. I don't believe that bearing spacers are available for a 2.45 to 2.30 main bearing, but you can offset grind the 2.1 diameter rod journal for either more or less stroke and use the 2" rods. I have a 4 bolt main 331 (.030 ) in my Jimmy with over 100k miles on it. Another option (and my favorite) would be to build a 302 using either an aftermarket 3.00" stroke crank and a large journal 350 block or a 283 crank in a small journal 327 block. The 302 (67-69 Z/28 engine)would be a blast to drive with a power band approximating that of the 2.4L engine, with double the power output. Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted July 19, 2001 Share Posted July 19, 2001 thanks for the tips mike! - and yes, this is an AWESOME board. I think that anyone building ANY type of custom engineered car could benfit from these forums greatly. - just about everything i've learned about cars i learned here! Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted July 19, 2001 Share Posted July 19, 2001 what year model 350 blocks should i look for to build the destroked 327? all i need a block with a 4" bore and 2.45 (large) main journals right? Quote Link to comment Share on other sites More sharing options...
Mike C Posted July 19, 2001 Share Posted July 19, 2001 Anything before 1980 should have a drivers side dipstick and two piece rear seal. Look to trucks for 4 bolt mains. Behind the timing cover if it has the numbers 010 and 020 it is a higher nickel content than a block with 010 and 010 (same number twice or just one number)The higher nickel content makes for a more wear resistant cylinder bore. 3970010 is the most common casting number and was either two or four bolt main. 1981-1985 have passengers side dipstick and two piece rear main seal. In 86 they switched to one piece rear seal, and most motors by 87 were hydraulic roller cam. To use the GM large journal crank you'll have to stick with one piece rear seal. If 327 is the goal, northernautoparts.com has a hi-perf 327 setup with the following for the garage sale price of $439.99: INCLUDES Hasting Moly Rings TRW Forged flattop Piston Clevite Rod Brgs Clevite Main Brgs Clevite Cam Brgs Melling Hivolume Oil Pump Crane Energizer Camshaft and Lifter Kit Cloyes TRUE Roller Timing Components Pioneer Frost Plugs Felpro Gaskets Regardless of what you decide, run a cylinder head with at least 2.02/1.6 valves and closed chambers (64-67cc) Can't beat the AFR 190's for power output, but $1250 a pair assembled. Next choice would be Dart 215s at $499 apiece. [ July 19, 2001: Message edited by: Mike C ] Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 20, 2001 Share Posted July 20, 2001 for a four bolt main, i dont know what they do to make them so, but i saw them advertised in hot rod, or super chevy, i was interested in them a lot for a split second, but then "mine aint broke" the 327 has a great sound to it and a nice power curve that lends itself great to a z. it revs a little faster than a 350 with a whole different response. from my experiences drivng 350 powered cars, (01 ss camaro, irocs, caprices) they make good power in this slow revving manner making gobs of torque down low, that is great, but the 327 sounds like a chainsaw ripping through its narrower powerband, from 3k-5800 its a pure symphony of power!!!!!! i launch that dog at 2800 with a minimal amount of tirespin(i do have to feather the clutch and modulate the gas out the hole) if you have the money, destroke that 327 and make it happen. 3892657-is the one for me! my 327 is out of the camaro, rs i think, the four barrel with the camel hump heads. its pretty stock high compresssion motor, if youre budget is pretty high skys the limit, my recipe for a cheap rev to 7500 all damn day motor is: steel crank steel rods 11-1 pistons the high performance solid lifter 327 vette cam (cost is cheap from just about anyone) and you gotta love em 2.02/1.60 camel hump heads, maybe get a valve job and street pocket porting, everything listed above is factory issue from the old school, a little hei and maybe use the dz 302 manifold (aftermarket ones are cheaper than weiand or holley) and a 650 carb and bolt up the muncie and get ready to take your crown! this should put out about 350-400hp and the same for torque, with high revving chainsaw powerband... you can find these blocks and heads everywhere, and all the other parts the same deal. if you really want to do it hard, stick a blower on it and use 8-1slugs and youll have closer to 500 horse with one carb! just my views, as i much as i like the 327, the LT1 keeps begging me to give him a chance. Leonard Quote Link to comment Share on other sites More sharing options...
Mike C Posted July 20, 2001 Share Posted July 20, 2001 All of the small journal engines had steel cranks. All small blocks until recently had forged rods. New ones are powdered metal with "cracked" caps. A studded 2 bolt block is as good as 4 bolts. The combustion chambers of the old double humps are dated and require lots of ignition lead. (I run several sets myself so I ain't doggin' 'em.)But why spend $600 rebuilding the old ones after paying $200+ dollars for cores when brand new heads are less. As far as the mechanical lifter cam, it was designed in the late 50's and they have learned a lot since. A Comp 282S(s for solid lifter) will make more power, get better mileage and have a nicer idle at the cost of a few bucks. But it's nice to have the quiet valvetrain of hydraulic lifters. The Holley 300-36 is pretty much a duplicate of the old DZ302 intake for about $110. I still think a 302 "Chebby" is the ulitmate Z car motor. And mine is slowly coming together ;-)I can't argue with the LT1 being a great swap (Not the LT-1 i.e. 70 Z/28)since the ol' "optispark" eliminates the distributor and my guess is the need to modify the hood latch. Quote Link to comment Share on other sites More sharing options...
Peternell Posted July 20, 2001 Share Posted July 20, 2001 Mike, I gotta take exception to ALL SJ engines had steel cranks. That was true up until ? 1964 or 1965, the GM put cast cranks in engines that they deemed didn't need a steel crank (ie lower performance engines) I've had and torn down several SJ engines over the last 5 years and have had several cast SJ cranks, most of them however were the 3" stroke 283 cranks. I do however agree the 302 Chev would be a GREAT Z car engine. Later Larry Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 21, 2001 Share Posted July 21, 2001 i agree, DZ302 is a great great motor, if i didnt have a great running 327, it would be a 302 all dang day! i dont like the low end grunt in a z, i like em making power a little higher up, and thats what both motors do so well.... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 12, 2001 Share Posted December 12, 2001 not sure if this was already said but..... a large journal 350 and 327 use the same 5.7" rod with a different piston. both are 4" bore. the blocks or a large journal 327 and 350 are the same unless you go new enough to get a different dipstick location or you get a 4 bolt main. buy a 350.....buy steel crank and hyper pistons....have reasonably cheap motor with fresh guts and plenty of power. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 12, 2001 Share Posted December 12, 2001 302 i think its ideal for a 240z, might want a little more for a 280z(C.I. that is) more low speed torque. my 2380lb 240 would leave me at 2500 with the 8 cyl and the fact that you can use a t5 and save the moola and weight and complexity of the t56! works for me!! set of pistons only 800 bucks Quote Link to comment Share on other sites More sharing options...
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