We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

SBC head with dual heat crossover ports.

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
rfoll
Guru
Guru
Posts: 2492
Joined: Mon Jan 11, 2010 12:44 pm
Location: St. Helens, OR

SBC head with dual heat crossover ports.

Post by rfoll » Tue Dec 03, 2019 2:43 pm

I am planning to use a set of heads that have the heat crossover in both center exhaust ports. I have heard they are crack pron, and recently have seen it on a pair of low mile heads. Is there an advantage to blocking one port of each pair of restricting both ports by some means? I have this thought of inserting a small tube in each port and pouring zinc or aluminum around it, or just pouring one of them shut. I do need carb het for wintertime driving. It was 19 degrees Saturday morning..
So much to do, so little time...

jeff swisher
Guru
Guru
Posts: 1084
Joined: Wed May 23, 2007 11:13 am
Location: yukon ok.
Contact:

Re: SBC head with dual heat crossover ports.

Post by jeff swisher » Tue Dec 10, 2019 9:25 am

All that crack prone nonsense is just that.
I have ran the 624 castings which have dual passages.. never cracked one and all of them were ported.
I now run the 601 HO 305 heads and they also have dual passages and I never cracked one of those.

I have received cracked heads in all types and I assume the cracks got there because people do not keep the temps in check or they allow the engine to run under load pinging.

Keep timing in check and coolant in check and your heads will live forever.
I have personally seen an engine with dual crossover heads with over 400,000 miles and another with over 300,000 miles on it.

My 601 casting heads have over 100,000 miles on them after I ported them and I run 10.87 compression under them, they see towing duty and drag strip duty often.
7000 rpm shifts not an issue either.

Here is my 4 door 57 with 601 heads no filling of the ports just regular porting stuff and the stock 1.84-1.50 GM valves.
10.87 compression 280H cam TH 350.
Racing against my buddies 2015 supercharged mustang. I told him he would have to try and catch me. He could not.


Walter R. Malik
Guru
Guru
Posts: 4836
Joined: Tue Jul 24, 2012 11:15 am
Location: Roseville, Michigan (just north of Detroit)
Contact:

Re: SBC head with dual heat crossover ports.

Post by Walter R. Malik » Tue Dec 10, 2019 9:56 am

rfoll wrote:
Tue Dec 03, 2019 2:43 pm
I am planning to use a set of heads that have the heat crossover in both center exhaust ports. I have heard they are crack pron, and recently have seen it on a pair of low mile heads. Is there an advantage to blocking one port of each pair of restricting both ports by some means? I have this thought of inserting a small tube in each port and pouring zinc or aluminum around it, or just pouring one of them shut. I do need carb het for wintertime driving. It was 19 degrees Saturday morning..
They are crack prone ONLY if the exhaust gasses get to hot for long periods of time such as with retarded ignition timing or incorrect fuel mixture, etc.

I have never seen an issue if everything else in the engine remains right.
http://www.rmcompetition.com
Specialty engine building at its finest.

rfoll
Guru
Guru
Posts: 2492
Joined: Mon Jan 11, 2010 12:44 pm
Location: St. Helens, OR

Re: SBC head with dual heat crossover ports.

Post by rfoll » Tue Dec 10, 2019 10:02 am

That is what I suspected, many of these engines experience rough lives with the "drive it till it drops" mentality. Jeff, I see you enjoy beating up Mustangs as much as I do.
So much to do, so little time...

jeff swisher
Guru
Guru
Posts: 1084
Joined: Wed May 23, 2007 11:13 am
Location: yukon ok.
Contact:

Re: SBC head with dual heat crossover ports.

Post by jeff swisher » Tue Dec 10, 2019 10:10 am

I see you enjoy beating up Mustangs as much as I do.
All my buddies want to beat me and and it happens to be a Mustang every now and then.

He sold that car 2 weeks after the race and had me build him a 355" for his short bed Chevy truck.
He has since beat up on a newer 5.0 mustang himself with his truck!
I think he may be able to beat me in my 57.. but i currently have it tuned and set up for pulling my 20 foot pontoon boat.
I will still race him when he is ready. :)

Post Reply