[novadose]

This is a question asking opinions on for a friend he works over seas and not able to post. He has a 482 bbc,with 14/71 blower and alcohol injection. Engine was built by a reputable company,ran the motor for a few passes to get a baseline and decided he wanted to go with a set of AJPE billet heads.Took the motor back to them to let them make the changes. Switched to [email protected] shaft setup and new pushrods. when he picked the motor up the first thing he noticed was it had 3/8 pushrods in it which he questioned them about,and they assured him it would be fine.Well first burnout it drops a cylinder,pull valvecover and find 2 bent pushrods and a busted lifter. Long story short not bashing engine builder just wanting opinions on what size pushrods you guys suggest.I know need more details but trying to keep short as possible, spring pressure around 380 on the seat and 1100 open. thanks in advance for any replys.

 

[Ron Clevenger]

If he's going to be buying new ones go with 1/2". I highly recommend calling Smith Bros Pushrods and discussing it with them.

Blessings........Ron.

 

[FlyinOhioan]

At least 7/16 on the intake side and 1/2" on the exh side with the thick wall tubing . A lot of the lifter wheel busting and pushrod bending probs can be tune up related .

 

[wicked nova]

I run 1/2 inch manton pushrods t&d shaft rockers with triple springs and titanium valves=bullet proof

 

[Sam Vincent]

Give Terry Manton a call. I run 7/16-1/2" tapered intake and 1/2-9/16" tapered exhaust pushrods on my small block nos engine, springs 425#seat/near1200# open

 

[novadose]

Thanks guys for the replys that's what we were thinking atleast 7/16 if not 1/2. Never had a problem until the change. He had 7/16 before the head change.

 

[NOS-Nelson]

1/2" Manton is the way to go.

 

[Sam Vincent]

Thanks guys for the replys that's what we were thinking atleast 7/16 if not 1/2. Never had a problem until the change. He had 7/16 before the head change.

wall thickness too. Manton has .120", .145", .156", .168", .188" wall depending on the diameter.

 

[SHAWN DAVIS]

A 7/16 .120 wall would work, Does it have stainless or titanium valves?
I cant believe they tried a 3/8 pushrod in that application.

 

[novadose]

Yes it has ti int and exh. Motor has pretty much best of everything. Like I said he was concerned about the pushrods. When he picked the motor up asked them several times and asuured him they would be fine. When it dropped cylinder. Took it back to them and was told lifter failed. Once again no bashing or naming the company jus wanted some opinions. It has a Dennis Parano fuel system and run his jet program so don't see it being a tuning issue.

 

[morris]

You can not put to big a pushrod in it. I have had 9/16 in some hemi stuff I did.

 

[novadose]

Thanks for the replys,going with a set of tapered 7/16...1/2'' mantons this time.

 

[scott foxwell]

This is a question asking opinions on for a friend he works over seas and not able to post. He has a 482 bbc,with 14/71 blower and alcohol injection. Engine was built by a reputable company,ran the motor for a few passes to get a baseline and decided he wanted to go with a set of AJPE billet heads.Took the motor back to them to let them make the changes. Switched to [email protected] shaft setup and new pushrods. when he picked the motor up the first thing he noticed was it had 3/8 pushrods in it which he questioned them about,and they assured him it would be fine.Well first burnout it drops a cylinder,pull valvecover and find 2 bent pushrods and a busted lifter. Long story short not bashing engine builder just wanting opinions on what size pushrods you guys suggest.I know need more details but trying to keep short as possible, spring pressure around 380 on the seat and 1100 open. thanks in advance for any replys.

I'm guessing ex pushrods? Engine builders not familiar with big boost blown engines don't understand how much cyl pressure the ex valve is opening against, and tend to figure pushrods on valve spring pressure like you would a NA engine. I agree with Steve...you can't install too big of a pushrod on deals like this.

 

[Sam Vincent]

I'm guessing ex pushrods? Engine builders not familiar with big boost blown engines don't understand how much cyl pressure the ex valve is opening against, and tend to figure pushrods on valve spring pressure like you would a NA engine. I agree with Steve...you can't install too big of a pushrod on deals like this.

Agree'd. Sure I dont have as much cyl. press. as a blown engine, but got 1/2" to 9/16" tapered pushrods on exh. on my SBF/nos engine.