Porting a stock LT5 - ZR-1 Net Registry Forums

Eric870 · 06-02-2010

Need info on Porting. Lots of Info (Links).

So what is the best set-up for a Stock engine?

Is there any advantage to porting the Heads on a Stock engine?

How big should the porting be? 35MM/34MM

Tools, what are the best tools for this job? Die grinder bit sizes ect..?

A1990 · 06-02-2010

36mm and yes port the heads.

Eric870 · 06-02-2010

Quote:

Originally Posted by A1990

36mm and yes port the heads.

Dennis, You have a 368. How much air is enough for a stock 350?

1989ZR1#74 · 06-02-2010

Quote:

Originally Posted by A1990

36mm and yes port the heads.

And paint them Atomic Orange right?

LGAFF · 06-02-2010

Porting heads is a tricky piece, I have seen a few heads sent to the gods of speed due to misalligned porting....and ZR-1 heads are not easy to find and not easy to fix. Watch out for water jackets.

Eric870 · 06-02-2010

Quote:

Originally Posted by LGAFF

Porting heads is a tricky piece, I have seem a few heads sent to the gods of speed due to misalligned porting....and ZR-1 heads are not easy to find and not easy to fix. Watch out for water jackets.

I do not want to F..up the heads. Risk vs. reward. Is it worth it? I do not want to mess with the engine it seems to me to be a low mile motor. I'm thinking maximize with bolt on?s and top end porting. But I have no fear it is a spare motor

LGAFF · 06-02-2010

I am a big do it yourself person, but if you do not know the weak points of the head, you need to stay smaller on ports, going 35/36 is a recipe for disaster......you can damage the area under the lifter or go through a water jacket, there are some very thin spots, and even people with experience have trashed sets.

Pete is not cheap but I know he is an expert at it. I have done a lot of intakes but I would not wander down a head port without a guide to help.

Be careful.....

Eric870 · 06-02-2010

Quote:

Originally Posted by LGAFF

I am a big do it yourself person, but if you do not know the weak points of the head, you need to stay smaller on ports, going 35/36 is a recipe for disaster......you can damage the area under the lifter or go through a water jacket, there are some very thin spots, and even people with experience have trashed sets.

Pete is not cheap but I know he is an expert at it. I have done a lot of intakes but I would not wonder down a head port without a guide to help.

Be careful.....

Lee, that very good advice and based on your advise I?m planning on staying away from the heads. One of the reasons I bought the engine is so I could "do it myself" and learn.

LGAFF · 06-02-2010

Port matching the head is ok, if you go 35-36 on the intake, port match the heads so that the transition is good, but then only go into the head with a taper about an 1" or 2" into the head, also, the port match will not be a circle pattern, it will be a cresent....if you have questions, more than happy to talk, or reach out to the pros.....Pete, Ryan, etc.

No need to port the 2ndry in the head on a port match.

A1990 · 06-02-2010

Quote:

Originally Posted by 1989ZR1#74

And paint them Atomic Orange right?

Naw, that's my thing...Pete won't work on them if you paint them AO

06-02-2010	#1
Eric870 Join Date: Apr 2009 Location: Portland OR Posts: 165	Porting a stock LT5 Need info on Porting. Lots of Info (Links). So what is the best set-up for a Stock engine? Is there any advantage to porting the Heads on a Stock engine? How big should the porting be? 35MM/34MM Tools, what are the best tools for this job? Die grinder bit sizes ect..?

06-02-2010	#2
A1990 Join Date: Dec 2003 Location: Grand Island NE Posts: 1,512	Re: Porting a stock LT5 36mm and yes port the heads. __________________ Dennis Fierstein 90 ZR-1 #2562 Atomic-Z ZR-1 Net Registry Chairman of the Board ZR-1 Net Registry Treasurer

06-02-2010	#5
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Porting a stock LT5 Porting heads is a tricky piece, I have seen a few heads sent to the gods of speed due to misalligned porting....and ZR-1 heads are not easy to find and not easy to fix. Watch out for water jackets. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 Last edited by LGAFF; 07-17-2010 at 11:20 AM.

06-02-2010	#9
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Porting a stock LT5 Port matching the head is ok, if you go 35-36 on the intake, port match the heads so that the transition is good, but then only go into the head with a taper about an 1" or 2" into the head, also, the port match will not be a circle pattern, it will be a cresent....if you have questions, more than happy to talk, or reach out to the pros.....Pete, Ryan, etc. No need to port the 2ndry in the head on a port match. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

06-02-2010	#7
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Porting a stock LT5 I am a big do it yourself person, but if you do not know the weak points of the head, you need to stay smaller on ports, going 35/36 is a recipe for disaster......you can damage the area under the lifter or go through a water jacket, there are some very thin spots, and even people with experience have trashed sets. Pete is not cheap but I know he is an expert at it. I have done a lot of intakes but I would not wander down a head port without a guide to help. Be careful..... __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 Last edited by LGAFF; 10-29-2016 at 05:42 PM.