Help/?? with BBC pushrods
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 3,472
Likes: 18
From: Lake Ozark, MO
Help/?? with BBC pushrods
Looking at roller rockers set up for a new 454 engine I'm building. What is the stock pushrod setup 3/8 or 7/16? All the aftermarket rollers show/require 7/16 guideplates. Just a heavier duty setup?? I noticed on my engine some of the pushrods are two piece.... If someone could explain..........
Burning Brakes
Joined: Feb 2004
Posts: 958
Likes: 1
From: In the Beautiful Shenandoah Valley of VA
Various 454s came with either 3/8 or 7/16 pushrods. I believe the "standard" performance engines came with the smaller diameter, with the stronger engines having 7/16 diameter pushrods. Having said that, I believe the parts catalog may have even listed three different sizes when I was trying to replace the bent and broken ones on my '74 LS-4.
I suspect the aftermarket sizes pushrods in 7/16 only, since they would be looking at the strength issue (high rpm). I can't explain the two-piece units that you are referring to on your engine without a picture, however, in many cases, an engine builder may want to change the length of the pushrod to make for correct rocker arm geometry. Your engine may be the recipient of pushrods designed to make changing the length easier.
Steve
I suspect the aftermarket sizes pushrods in 7/16 only, since they would be looking at the strength issue (high rpm). I can't explain the two-piece units that you are referring to on your engine without a picture, however, in many cases, an engine builder may want to change the length of the pushrod to make for correct rocker arm geometry. Your engine may be the recipient of pushrods designed to make changing the length easier.
Steve
Thread Starter
Melting Slicks
Joined: Mar 2004
Posts: 3,472
Likes: 18
From: Lake Ozark, MO
THis is the first chevy I've toyed with in a long time and something makes me want to add the rollers (not sure if they are really needed or not) while the engine is apart. I'll check to see what pushrods I have when I go home. I'm assuming the 7/16 pushrods can be used on a 3/8 engine if the guide plates are changes? Don't have to do anything with the lifters do I?
Mike
Mike
Race Director
Joined: Nov 2002
Posts: 12,142
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From: Taylor Michigan
Originally Posted by Hvymtlc5
Looking at roller rockers set up for a new 454 engine I'm building. What is the stock pushrod setup 3/8 or 7/16? All the aftermarket rollers show/require 7/16 guideplates. Just a heavier duty setup?? I noticed on my engine some of the pushrods are two piece.... If someone could explain..........
Advanced
Joined: Sep 2004
Posts: 50
Likes: 0
Originally Posted by Hvymtlc5
THis is the first chevy I've toyed with in a long time and something makes me want to add the rollers (not sure if they are really needed or not) while the engine is apart. I'll check to see what pushrods I have when I go home. I'm assuming the 7/16 pushrods can be used on a 3/8 engine if the guide plates are changes? Don't have to do anything with the lifters do I?
Mike
Mike
Le Mans Master
Joined: Dec 2003
Posts: 5,727
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From: Fremont CA
7/16" was L-88 hardware. Today in "modern times" we use 3/8" push-rods in BB Chevy's because the 7/16" stuff weighed a TON and although they are stronger, they can cause valve float due to their excessive weight. Roller rockers won't necissarily add a lot of HP but, will reduce oil tempratures and give you consistant rocker arm ratios. I like the Comp Cams Pro Magnum steel roller rockers over aluminum rockers (unless you go the "shaft" rocker route.)
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Originally Posted by Solid LT1
7/16" was L-88 hardware. Today in "modern times" we use 3/8" push-rods in BB Chevy's because the 7/16" stuff weighed a TON and although they are stronger, they can cause valve float due to their excessive weight. Roller rockers won't necissarily add a lot of HP but, will reduce oil tempratures and give you consistant rocker arm ratios. I like the Comp Cams Pro Magnum steel roller rockers over aluminum rockers (unless you go the "shaft" rocker route.)
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Burning Brakes
Joined: Feb 2004
Posts: 958
Likes: 1
From: In the Beautiful Shenandoah Valley of VA
Standard pushrods for a hydraulic cammed big block chevy is 5/16. Performance solid lifter engines from GM used a 3/8 pudhrod in the early models. Some subsequent high horsepower solid lifter engines were also 7/16 equiped. In any event, to use the larger diameter push rods even on the hydraulic cam engines will require matching guide plates. Some of the larger performance push rods were a different material part way up where it would go through the guide plates.
Steve
