Head Porting 041 Casting
Thread Starter
Melting Slicks
Joined: Apr 2010
Posts: 2,796
Likes: 1,197
From: Canberra Australia
2025 C3 of the Year Finalist - Modified
Head Porting 041 Casting
Hi
Can I get some advice please.
Am looking for some original steel heads to go on my 71 L48 to raise the compression and give better flow. It will stay with Q-Jet on original steel manifold (or possibly a Performer) with Flowtech headers.
Am only after modest gains.
I want it to look original so I am looking at
- 186 heads with 1.94 inlets - fairly stock but in good condition
- 041 heads with 2.02 inlets that have been heavily ported
I am no expert in this area at all so is it possible to have opened up the exhaust and inlet sides of the heads too much.
I look at the images and it looks like they are huge compared to the others i have looked at.
Would they need matched exhaust and inlet manifolds to use them
Any opinions would be appreciated.
Craig
Can I get some advice please.
Am looking for some original steel heads to go on my 71 L48 to raise the compression and give better flow. It will stay with Q-Jet on original steel manifold (or possibly a Performer) with Flowtech headers.
Am only after modest gains.
I want it to look original so I am looking at
- 186 heads with 1.94 inlets - fairly stock but in good condition
- 041 heads with 2.02 inlets that have been heavily ported
I am no expert in this area at all so is it possible to have opened up the exhaust and inlet sides of the heads too much.
I look at the images and it looks like they are huge compared to the others i have looked at.
Would they need matched exhaust and inlet manifolds to use them
Any opinions would be appreciated.
Craig
Le Mans Master
Joined: Oct 2010
Posts: 6,943
Likes: 850
From: melbourne florida
2023 C3 of the Year Finalist - Modified
depending on how well ported they are the could be a nice set of heads. all this information is relative, no they likely wont make more power than a set of a.f.r heads but compared to stock heads they should be lots better. alot of racers back in the day made 400+ h.p with those heads would newer stuff make more power, likely so. but were still cool in the old school.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 39
From: Fremont CA
Exhaust ports on those ported heads reflect early 70's logic they probably don't flow much better than a stock port. Heads have been highly ported and look like they will be prone to cracking. Go with some "virgin heads" but, you will be into them for more $$$ than a set of aftermarkets heads by the time they are properly finished. Try to sell the heads on Ebay and use the $$$ towards a set of decent heads.
Le Mans Master
Joined: Dec 2006
Posts: 5,557
Likes: 9
From: Oquirrh Mountains
St. Jude Donor '09
Go find a set of vortec heads from a 96+ chevy/gm vehicle. These will run $300 or so. Get a valve job, a vortec intake and be sure to grab the center bolt valve covers and you will be way ahead (pun intended) of those two heads you mentioned.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Exhaust ports on those ported heads reflect early 70's logic they probably don't flow much better than a stock port. Heads have been highly ported and look like they will be prone to cracking. Go with some "virgin heads" but, you will be into them for more $$$ than a set of aftermarkets heads by the time they are properly finished. Try to sell the heads on Ebay and use the $$$ towards a set of decent heads.
Pro
Joined: Jan 2004
Posts: 535
Likes: 1
From: Darwin, Australia NT
I used to do this type of porting back in the mid 70's. We used to get well into the 10's back then with stock ported iron heads, big solid lifter cams, open headers and an intake hogged out to match the heads with a big holley double pumper on it. M22 4 speed, 4.11 gears, traction bars and slicks. 350, No stroker, no roller cam, 5000 RPM launches with8000 RPM shifts. Old school was pretty fast. That said those ports are better for high RPM use would actually hurt your bottom end performance on a street 350.
