Dumb Roller Rocker Question

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Jan 8, 2006 | 07:05 PM

Hogan

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From: First to Sign Grumpy's Hat Only 53 miles from Hell

St. Jude Donor '06-'09-'10-'11

Dumb Roller Rocker Question

Once I obtain steady employment I would like to get some roller rockers. I was thinking about getting 1.6's or the max I could go on my LT1 but I was thinking of staggering the ratio, as in 1.6 on the intake and 1.65's or 1.7's for the exhaust. A few years ago I remember a couple of Pontiac guys were running 1.6 on the intake and 1.7 on the exhaust to improve flow. I know the Pontiac heads did not flow as well as a SBC head but would this trick help??

Jan 8, 2006 | 07:17 PM

Nathan Plemons

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Personally I'd go with 1.7's on both if you're going to go with 1.7's at all. The LT1 heads should benefit by the added lift on both sides.

Jan 8, 2006 | 07:28 PM

Hogan

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From: First to Sign Grumpy's Hat Only 53 miles from Hell

St. Jude Donor '06-'09-'10-'11

Quote:

Originally Posted by Nathan Plemons

Personally I'd go with 1.7's on both if you're going to go with 1.7's at all. The LT1 heads should benefit by the added lift on both sides.

By going to 1.7's would I have to change out springs and pushrods?

Jan 8, 2006 | 11:51 PM

MYCoupe

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From: Hewitt NJ

If you're still using the stock springs, then yes you'll have to repace them.

Jan 9, 2006 | 11:07 AM

Hogan

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From: First to Sign Grumpy's Hat Only 53 miles from Hell

St. Jude Donor '06-'09-'10-'11

Quote:

Originally Posted by Admiral94

If you're still using the stock springs, then yes you'll have to repace them.

Ok, what about the push rods if I go with 1.7's?

Jan 9, 2006 | 12:04 PM

Nathan Plemons

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If you're really picky you'll get an adjustable length pushrod and do a bunch of measuring to figure out the exact length that you may need. Being said I've been running 1.7's on my car for over 19k miles without any troubles.

Jan 9, 2006 | 12:42 PM

Hogan

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From: First to Sign Grumpy's Hat Only 53 miles from Hell

St. Jude Donor '06-'09-'10-'11

Quote:

Originally Posted by Nathan Plemons

If you're really picky you'll get an adjustable length pushrod and do a bunch of measuring to figure out the exact length that you may need.

Doesn't CompCams or other companies sell the correct pushrod for such an application?

Bout how much hp do you think 1.7's would pick up? Should there be any tuning afterwards to optimize having the rockers?

Sorry for the dumb questions.

Jan 9, 2006 | 01:29 PM

Nathan Plemons

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Yes several companies sell pushrods of various different lengths, but exactly what you may need depends on your setup. On a rebuild say you had the heads milled and used a thinner head gasket. You might need a shorter pushrod than somebody who has stock heads and stock head gaskets. As such there is absolutely no way that comp cams could keep an accurate list of what exact pushrod you need for what exact configuration.

1.6 rockers on an otherwise stock LT1 are supposed to give you 10-15 RWHP. I don't know that anybody has ever tried 1.7's on a stock LT1 so I really can't quantify a gain for you. The numbers indicate that there should be a gain, but I've never seen data to give a number on it.

FYI it would be highly recommended to change your springs just by going with 1.6's and it will be absolutely required if you go with 1.7's.

Tuning will never hurt and should be considered especially if the car is speed density and doesn't have a MAF sensor.