New Member-Tuning Issue? - Forums - Official C3 Vette Registry

New Member-Tuning Issue? (20/29)
8/13/10 1:55pm

anips
Former Member
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 784

the short block sounds fine to me, Dry has a little over 9.5 compression according to the paper work and if they surfaced both the block and heads it might be closed to 10to1 which is good, the cam sounds alright to me, I compared it to the chevy L79 cam that came in the special performance 327 350hp motors that came in the corvette, Nova that had 11to1 motors, if you ever had one you know they were a great street cam that produced great power and torque straight up, Drys cam is just about identical but a hair smaller, my guess its in the heads or the ign. setup, port and polish nowadays with a die grinder is an art form which needs a flow bench, CNC would be the way to go, but I don't know how or what was done, good luck. anips2010-08-13 11:42:33

New Member-Tuning Issue? (21/29)
8/13/10 3:05pm

Lifetime Member
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Hot Springs, AR - USA

Vette(s):
69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans

Joined: 4/24/2004
Posts: 3231

anips.. i disagree... no offense dry but I think you had some schizophrenia in the design of the engine. some things seem to have been done to maximize top end HP and others to maximize low end torque. you can set things up in conflict and achieve nothing. I dont think he is getting 10:1 out of it. assuming 9.5 on block after surfacing and just from surfacing heads you might get 9.7

that is still quite aways from 11:1.

the l-79

The 327-350hp "L-79" cam is 221in 221ex duration @.050" .447" .447" lift 114LSA. Commonly referred to as the "151" cam. Needs 10:1+cr and 4.10's. A 2800/3000stall converter helps too.

he has neither the 10+ or 4.10 gears.. and probably isnt dropping the clutch at 2800-3000 either.

the 68 vette with the 327/350 produced 350 hp @ 5800 and 360 lb ft @ 3600rpm wth 11:1 compression.

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New Member-Tuning Issue? (22/29)
8/13/10 6:47pm

anips
Former Member
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 784

Ben, I used the l-79 as a comparision, Dry's cam is smaller in all areas accept for max lift which is .003 more, GM reccomends a compression ratio of 9:5- 10:75 for the l-79 cam, he's in the ball park lookin for his seat.....my new 66 SS L-79 Nova came with 3:73gear and the performance gr.'s for 66-67 327 350 hp vette's were also 3:73's, ...what do you suggest he do?

anips2010-08-13 18:38:11

New Member-Tuning Issue? (23/29)
8/14/10 8:31pm

[QUOTE=anips]

[/QUOTE]

i suggest he not expect any low end torque.

I did enter all the parameters into desktop dyno and when in doubt I gave him the benefit of the doubt and went higher.. ie 10.0 compression. even advanced the cam by the 4 degrees.

in his curent config ... his peak horse is about 290 @ 5500 and his peak torque is 295 or so @ 4500.

the biggest improvement he can make with that cam is ditch the ex manifolds and run headers

small tube headers have a slight advantage on the torque side and large tube have a slight advantage on hp side.

using small tube headers with mufflers moves his peak hp up to 371@6000 and peak torque to 364@4500

cthulhu2010-08-14 18:29:35

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New Member-Tuning Issue? (24/29)
8/14/10 11:34pm

http://direclynx.net/~cthulhu/manifolds.jpg

check these out

manifolds

headers

http://direclynx.net/~cthulhu/headers.jpg

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New Member-Tuning Issue? (25/29)
8/15/10 12:06am

anips
Former Member
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 784

there ya go, much better, when you did your pull did you program in long or short headers and did the small tube headers have 1 1/2" ID primary's ? anips2010-08-15 06:43:25

New Member-Tuning Issue? (26/29)
8/15/10 10:07pm

dry
Former Member
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tulsa, OK - USA

Vette(s):
74 L82 4 Speed Orange/Saddle

Joined: 8/6/2010
Posts: 7

[QUOTE=cthulhu][QUOTE=anips]

[/QUOTE]

i suggest he not expect any low end torque.

I did enter all the parameters into desktop dyno and when in doubt I gave him the benefit of the doubt and went higher.. ie 10.0 compression. even advanced the cam by the 4 degrees.

in his curent config ... his peak horse is about 290 @ 5500 and his peak torque is 295 or so @ 4500.

the biggest improvement he can make with that cam is ditch the ex manifolds and run headers

small tube headers have a slight advantage on the torque side and large tube have a slight advantage on hp side.

using small tube headers with mufflers moves his peak hp up to 371@6000 and peak torque to 364@4500

[/QUOTE]

Thanks guys that is the type of information i am looking for i would just like to be able to optimize my current set up. What headers anybody have any ideas for a good brand? diameter?

Thanks

New Member-Tuning Issue? (27/29)
8/16/10 12:05am

anips
Former Member
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 784

I run hooker "long under chassis headers small tube 1 1/2" ID or 1 5/8 OD with a 3 1/2" collector on the LT-1, my engine is a 30 over 350 9:75 comp forged flat tops, stock Lt-1 bottom end with the stock Lt-1 solid lifter cam straight up, stock 202- 160 heads "performance Distributor" dist. 3:55 ger. stock ratio1.5 roller rockers,works for me, you might ask Ben what header info he programed into the dyno run, glad to help. anips2010-08-15 21:09:17

New Member-Tuning Issue? (28/29)
8/16/10 10:29am

[QUOTE=anips]I run hooker "long under chassis headers small tube 1 1/2" ID or 1 5/8 OD with a 3 1/2" collector on the LT-1, my engine is a 30 over 350 9:75 comp forged flat tops, stock Lt-1 bottom end with the stock Lt-1 solid lifter cam straight up, stock 202- 160 heads "performance Distributor" dist. 3:55 ger. stock ratio1.5 roller rockers,works for me, you might ask Ben what header info he programed into the dyno run, glad to help. [/QUOTE]

I just used generic small tube headers... those sound good

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New Member-Tuning Issue? (29/29)
9/1/10 8:11am

Gary Lacoursiere
Former Member
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, - Canada

Vette(s):
1976 L-48 Coupe Vortec Heads; Roller Rockers, 625 Demon, 700R4; Electric fan, Aluminum Rad, Full-lenght headers w/ sidepipes, fiberglass bucket w/ 5-point quick release harness.

Joined: 7/19/2010
Posts: 10

I agree with the headers. Any full-lenght, small-tube headers will boost your bottom end. Also, like one of the guys suggested, try dumping the clutch at 3000-3500 RPM. By that point, you're into your cam and you will be sideways before you know it, smoking the skins like a 16-year old!!