Using stock size pushrods?
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Car: 85 Iroc-Z
Engine: 383 TPI Procharger D1SC
Transmission: TKO600
Axle/Gears: Strange S60 3.73
Using stock size pushrods?
I am building a 383 for my car from scratch and have a question about the pushrods. I am not using stock parts, (comp cams xfi cam, afr heads), but will I still be able to use the factory size pushrods for a roller cam motor?
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Re: Using stock size pushrods?
Even if they would fit, and they're probably now too short, they flex too much for use with an XFI cam. At this point, all they're good for is checking your valvetrain geometry once you get the new combo together.
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Re: Using stock size pushrods?
Length should always be checked especially with a head swap to achieve the proper valve train geometry.
I'd recommend upgrading to 3/8" pushrods from the stock 5/16" ones. They won't deflect so much trying to compress heavier than stock valve springs.
I'd recommend upgrading to 3/8" pushrods from the stock 5/16" ones. They won't deflect so much trying to compress heavier than stock valve springs.
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Re: Using stock size pushrods?
Do I need to change anything to upgrade to 3/8 inch or will they simply just go right in without modifications? The heads have guide plates also, so will clearance be an issue with the bigger pushrods?
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Re: Using stock size pushrods?
I will just go with a pushrod length checker then. What adjustment range should I buy the checker in? Will there be that much of a difference by going up to a 3/8 inch? I didn't think I would have any deflection problems by going with a chromemoly and using the guideplates.
Last edited by 85Iroc-Z; 04-01-2010 at 06:07 PM.
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Re: Using stock size pushrods?
Stock SBC pushrods are 7.800" long.
You really don't need to upgrade to 3/8" pushrods but it won't hurt. I doubt you have enough spring pressure where 3/8" pushrods are required. My valve springs have over 200# on the seat and over 800# open and 3/8" pushrods are still surviving. For me a 7/16" or tapered pushrod would be better. The best thing to do to get a stronger pushrod is to buy them with thicker walls. 0.080" is a standard heavy wall pushrod. Factory pushrod walls are very thin. Something like 0.065". Extreme thickness is around 0.120"
When using a pushrod length checker, you will need some lightweight checking springs. If you try to compress the regular valve springs with the checking rod, it will bend or break.
It's unlikely you'll have shorter than stock length pushrods but you have a few options for a checking tool
Comp Cams 7901-1 measures from 7.500" to 8.700"
Comp Cams 7703-1 measures from 7.800" to 8.800"
Comp Cams 7711-1 measures from 7.800" to 8.800"
Pick up whichever one is available plus some checking springs. Proform, Comp Cams, Moroso etc all sell them.
For a SBC, you only need one adjustable pushrod checker and one pair of springs.
You really don't need to upgrade to 3/8" pushrods but it won't hurt. I doubt you have enough spring pressure where 3/8" pushrods are required. My valve springs have over 200# on the seat and over 800# open and 3/8" pushrods are still surviving. For me a 7/16" or tapered pushrod would be better. The best thing to do to get a stronger pushrod is to buy them with thicker walls. 0.080" is a standard heavy wall pushrod. Factory pushrod walls are very thin. Something like 0.065". Extreme thickness is around 0.120"
When using a pushrod length checker, you will need some lightweight checking springs. If you try to compress the regular valve springs with the checking rod, it will bend or break.
It's unlikely you'll have shorter than stock length pushrods but you have a few options for a checking tool
Comp Cams 7901-1 measures from 7.500" to 8.700"
Comp Cams 7703-1 measures from 7.800" to 8.800"
Comp Cams 7711-1 measures from 7.800" to 8.800"
Pick up whichever one is available plus some checking springs. Proform, Comp Cams, Moroso etc all sell them.
For a SBC, you only need one adjustable pushrod checker and one pair of springs.
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Re: Using stock size pushrods?
Stock SBC pushrods are 7.800" long.
You really don't need to upgrade to 3/8" pushrods but it won't hurt. I doubt you have enough spring pressure where 3/8" pushrods are required. My valve springs have over 200# on the seat and over 800# open and 3/8" pushrods are still surviving. For me a 7/16" or tapered pushrod would be better. The best thing to do to get a stronger pushrod is to buy them with thicker walls. 0.080" is a standard heavy wall pushrod. Factory pushrod walls are very thin. Something like 0.065". Extreme thickness is around 0.120"
When using a pushrod length checker, you will need some lightweight checking springs. If you try to compress the regular valve springs with the checking rod, it will bend or break.
It's unlikely you'll have shorter than stock length pushrods but you have a few options for a checking tool
Comp Cams 7901-1 measures from 7.500" to 8.700"
Comp Cams 7703-1 measures from 7.800" to 8.800"
Comp Cams 7711-1 measures from 7.800" to 8.800"
Pick up whichever one is available plus some checking springs. Proform, Comp Cams, Moroso etc all sell them.
For a SBC, you only need one adjustable pushrod checker and one pair of springs.
You really don't need to upgrade to 3/8" pushrods but it won't hurt. I doubt you have enough spring pressure where 3/8" pushrods are required. My valve springs have over 200# on the seat and over 800# open and 3/8" pushrods are still surviving. For me a 7/16" or tapered pushrod would be better. The best thing to do to get a stronger pushrod is to buy them with thicker walls. 0.080" is a standard heavy wall pushrod. Factory pushrod walls are very thin. Something like 0.065". Extreme thickness is around 0.120"
When using a pushrod length checker, you will need some lightweight checking springs. If you try to compress the regular valve springs with the checking rod, it will bend or break.
It's unlikely you'll have shorter than stock length pushrods but you have a few options for a checking tool
Comp Cams 7901-1 measures from 7.500" to 8.700"
Comp Cams 7703-1 measures from 7.800" to 8.800"
Comp Cams 7711-1 measures from 7.800" to 8.800"
Pick up whichever one is available plus some checking springs. Proform, Comp Cams, Moroso etc all sell them.
For a SBC, you only need one adjustable pushrod checker and one pair of springs.
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Re: Using stock size pushrods?
You have a roller cam... "stock" length in that system, is 7.400".
Doesn't too much matter though. More often than not, aftermarket stuff - bigger cams in particular - tend to require a longer size. But as Alky said, you MUST measure if you want the optimum fit.
Doesn't too much matter though. More often than not, aftermarket stuff - bigger cams in particular - tend to require a longer size. But as Alky said, you MUST measure if you want the optimum fit.
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Car: 82 Z28
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Re: Using stock size pushrods?
SBC Flat tappet pushrods are 7.800" long
SBC Roller cam pushrods are 7.200" long ( because roller lifter is taller than flat tappet lifter by .600" so pushrod is shorter)
Your final pushrod length requirement to suit your individual combo of heads / rockers will be within +/- .200" of the stock length so buy the pushrod checker that covers the length of what pushrod you " should " be using
I say " should" because you may be converting from flat to roller cam or vise versa
in which case you need pushrod length to suit what you are going to ;
not what you "had" before
Last edited by vetteoz; 03-13-2012 at 01:32 AM.
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Re: Using stock size pushrods?
Heads and rockers have nothing to do with it directly
SBC Flat tappet pushrods are 7.800" long
SBC Roller cam pushrods are 7.200" long ( because roller lifter is taller than flat tappet lifter by .600" so pushrod is shorter)
Your final pushrod length requirement to suit your individual combo of heads / rockers will be within +/- .200" of the stock length so buy the pushrod checker
that covers the length of what pushrod you " should " be using
SBC Flat tappet pushrods are 7.800" long
SBC Roller cam pushrods are 7.200" long ( because roller lifter is taller than flat tappet lifter by .600" so pushrod is shorter)
Your final pushrod length requirement to suit your individual combo of heads / rockers will be within +/- .200" of the stock length so buy the pushrod checker
that covers the length of what pushrod you " should " be using
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