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Difference between 327-300 and 327-350
Thread Starter
Instructor
Joined: Sep 2007
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From: Hollywood MD
Difference between 327-300 and 327-350
I have a 68 that came with the 327-300. It still has the original block but the guy I bought it from added fuelie heads, as he said. I guess those are the 2.02 intakes. Did the 300HP version come with 1.94 intake valves (double hump heads)? What other differences are there between the 327-300 and 327-350? Thanks
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
The difference is 50 HP.
Sorry, couldn't help myself.
Bigger valves. different cam, 11 to 1 comp vs 10 to 1. Think the 350 HP had a holley and 2.5" ramhorns but not sure.
Sorry, couldn't help myself.
Bigger valves. different cam, 11 to 1 comp vs 10 to 1. Think the 350 HP had a holley and 2.5" ramhorns but not sure.
Last edited by 63mako; Oct 11, 2007 at 08:22 PM.
Safety Car
Joined: Aug 2006
Posts: 4,102
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From: Forsyth Illinois
Some L79 cars came w/1.94 heads from the factory,or let me rephrase that......my numbers matching org. L79 short block to my 68 vert has 1.94 double hump heads(#291s)that the build dates are compatiable to the engines build date,so I am assuming here.They also,had the larger 8" finned balancer.Good engines....
Le Mans Master
Joined: Apr 2005
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From: Seattle Area WA
The heads are the same castings, the 300 should have the 1.94 intakes while the L-79 350 HP should have the 2.02s. The 300 used the smaller base motor cam "929" durations of 194/202, while the L-79 used the "151" cam, durations of 222/222. Base motors peaked out around 5,500 RPM and the L-79 a little over 6,000 RPM. The base motor used a cast iron intake and the L-79 used an aluminum mid rise intake, and aluminum valve covers. Actual compression was much lower than the advertised values by GM, the base motor was more like 9.5:1 and the L-79 more along the lines of 10.25:1.
Prior to '68, both motors began using the 2" exhaust manifolds.
Prior to '68, both motors began using the 2" exhaust manifolds.
Last edited by Scott Marzahl; Oct 12, 2007 at 12:01 PM.
Le Mans Master
Joined: Jan 2006
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
The heads are the same castings, the 300 should have the 1.94 intakes while the L-79 350 HP should have the 2.02s. The 300 used the smaller base motor cam "929" durations of 194/202, while the L-79 used the "151" cam, durations of 222/222. Base motors peaked out around 5,500 RPM and the L-79 a little over 6,000 RPM. The base motor used a cast iron intake and the L-79 used an aluminum mid rise intake, and aluminum valve covers. Actual compression was much lower than the advertised values by GM, the base motor was more like 9.5:1 and the L-79 more along the lines of 10.25:1.
Prior to '68, both motors began using the 2" exhaust manifolds.
Prior to '68, both motors began using the 2" exhaust manifolds.
except for one minor detail the 68 327 350 horse motor had chrome valve covers, while the 300 horse had painted ones
Le Mans Master
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From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
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Safety Car
Joined: Aug 2006
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From: Forsyth Illinois
Someone must of changed my heads w/perfect dated 291s w/1.94s for my HT code L79.Stranger things have happened.I don't think that there was a aluminum intake available for a SB vett in 68.They were 3919803,spreadbores.The numbers book shows only one intake available for the SB,and 7 aluminums for the BB.
Le Mans Master
Joined: Apr 2005
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From: Seattle Area WA
I think you are right. According to one book I just looked at, all '68 and '69 small blocks are listed as having received cast iron intake manifolds with the big blocks having aluminum ones. The aluminum intakes on the L-79 must have stopped with the '67 year.
Thread Starter
Instructor
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From: Hollywood MD
Good info. So my numbers on the block decode to a 327-300 but the guy I bought my vette from added an aluminum intake with a set of 2.02 heads, set of headers and holley carb. I like to keep the original engine block and the 2.02 heads. With a couple thousand dollar budget, can I get a fairly strong running 327 keeping the same heads out of this engine with a rebuild.
Thread Starter
Instructor
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From: Hollywood MD
I haven't thought it through completely. I want to harness as much out of it as possible and keep the costs down to about $2000. I'm open to suggestions for a good build from pistons to cam, lifters, rockers, intake and carb. I want to use the 2.02 heads. Thanks
Le Mans Master
Joined: Apr 2005
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From: Seattle Area WA
A 327 isn't going to be as torquey as a 350 due to the short stroke. These 327s are rev happy motors. A common and proven build is use the OEM type pistons, Federal Mogul L-2166, your '291 heads with 2.02 valves, I hope they are unshrouded for the larger valves, and pocket port them. Use a set of Crower Sportsman or an equivalent set of quality rods at a similar weight. Use a solid lifter cam like the LT-1 cam or simialr such as Crower's version, #00321 works very nice for a broad torqe curve and HP band from 1,800 - 7,200 RPMs.
Sure there are other choices, but this is a proven and reliable stick and combo. If you want zero maintenance, the "151" hydraulic cam works great with this compression ratio and will rev nicely to the low 6K range. Are there better cams, sure but these are a dead on reliable sticks for these motors built at 10.25-10.5:1 SCR.
Sure there are other choices, but this is a proven and reliable stick and combo. If you want zero maintenance, the "151" hydraulic cam works great with this compression ratio and will rev nicely to the low 6K range. Are there better cams, sure but these are a dead on reliable sticks for these motors built at 10.25-10.5:1 SCR.
