Angled plug vs straight plug heads prob
Thread Starter
Pro
Joined: Jun 2018
Posts: 532
Likes: 104
Angled plug vs straight plug heads prob
Woke up this morning jazzed that I would have the 89 Vette back on the road after being down for 2 Months.
I finished the engine I was rebuilding and I topped it off with a set of AFR enforcer 195 angle plug heads. I am using stock manifolds. I got the angle plug heads because the stock heads had the spark plugs going in at what looks like an angle so I figured "angled plug" is what I needed.
Well got the engine back in the car, got the distributor on and went to put in the spark plugs and the plugs hit the exhaust manifolds, I can't even screw them in. The "angle" on the AFR heads is much more dramatic than on the stock heads and it angles down instead of just angling away from the exhaust port.
Now I am at a loss for what to do. Will "straight plug" heads work? Should I recondition my stock heads? Are there any manifolds that will fit a Corvette and work with these heads?
While I am at it, do I need to pull the engine out again to swap the heads (I used studs when Installed the heads)?
Lousy day :-(
I finished the engine I was rebuilding and I topped it off with a set of AFR enforcer 195 angle plug heads. I am using stock manifolds. I got the angle plug heads because the stock heads had the spark plugs going in at what looks like an angle so I figured "angled plug" is what I needed.
Well got the engine back in the car, got the distributor on and went to put in the spark plugs and the plugs hit the exhaust manifolds, I can't even screw them in. The "angle" on the AFR heads is much more dramatic than on the stock heads and it angles down instead of just angling away from the exhaust port.
Now I am at a loss for what to do. Will "straight plug" heads work? Should I recondition my stock heads? Are there any manifolds that will fit a Corvette and work with these heads?
While I am at it, do I need to pull the engine out again to swap the heads (I used studs when Installed the heads)?
Lousy day :-(
Last edited by auburn2; May 27, 2024 at 01:03 PM.
Melting Slicks
Joined: Apr 2001
Posts: 2,112
Likes: 220
From: Ca.
I have an older version of the AFR 195 angle plug heads and they fit perfect with the original shape headers. Not sure what AFR changed-I would give them a call first and run it by them. You do need angle not straight plug to make things work easier. I would not keep the stock heads. If you need to pull the heads it's easily done without pulling the engine-just pull the studs-dont try to lift the heads off the studs. That does suck!
Thread Starter
Pro
Joined: Jun 2018
Posts: 532
Likes: 104
I have an older version of the AFR 195 angle plug heads and they fit perfect with the original shape headers. Not sure what AFR changed-I would give them a call first and run it by them. You do need angle not straight plug to make things work easier. I would not keep the stock heads. If you need to pull the heads it's easily done without pulling the engine-just pull the studs-dont try to lift the heads off the studs. That does suck!
Last edited by auburn2; May 27, 2024 at 03:31 PM.
Thread Starter
Pro
Joined: Jun 2018
Posts: 532
Likes: 104
Thanks. Did you buy your headers somewhere or modify the stockers?
I am going to pull the heat shields off tomorrow and see if that makes a difference. If it does, I will probably send the manifolds out to be coated and go without shields. If it still interferes I will probably call AFR for their advice.
I might also try some headers for a 92+ and see if I can get a local shop to weld the EGR flange on to them if the plugs fit.
I don't want to buy another set of heads and I really don't want to pull the engine again. I am doubtful I can get all the studs out with the heads on.
I am going to pull the heat shields off tomorrow and see if that makes a difference. If it does, I will probably send the manifolds out to be coated and go without shields. If it still interferes I will probably call AFR for their advice.
I might also try some headers for a 92+ and see if I can get a local shop to weld the EGR flange on to them if the plugs fit.
I don't want to buy another set of heads and I really don't want to pull the engine again. I am doubtful I can get all the studs out with the heads on.
Last edited by auburn2; May 27, 2024 at 07:04 PM.
Burning Brakes
Joined: Sep 2017
Posts: 938
Likes: 168
Woke up this morning jazzed that I would have the 89 Vette back on the road after being down for 2 Months.
I finished the engine I was rebuilding and I topped it off with a set of AFR enforcer 195 angle plug heads. I am using stock manifolds. I got the angle plug heads because the stock heads had the spark plugs going in at what looks like an angle so I figured "angled plug" is what I needed.
Well got the engine back in the car, got the distributor on and went to put in the spark plugs and the plugs hit the exhaust manifolds, I can't even screw them in. The "angle" on the AFR heads is much more dramatic than on the stock heads and it angles down instead of just angling away from the exhaust port.
Now I am at a loss for what to do. Will "straight plug" heads work? Should I recondition my stock heads? Are there any manifolds that will fit a Corvette and work with these heads?
While I am at it, do I need to pull the engine out again to swap the heads (I used studs when Installed the heads)?
Lousy day :-(
I finished the engine I was rebuilding and I topped it off with a set of AFR enforcer 195 angle plug heads. I am using stock manifolds. I got the angle plug heads because the stock heads had the spark plugs going in at what looks like an angle so I figured "angled plug" is what I needed.
Well got the engine back in the car, got the distributor on and went to put in the spark plugs and the plugs hit the exhaust manifolds, I can't even screw them in. The "angle" on the AFR heads is much more dramatic than on the stock heads and it angles down instead of just angling away from the exhaust port.
Now I am at a loss for what to do. Will "straight plug" heads work? Should I recondition my stock heads? Are there any manifolds that will fit a Corvette and work with these heads?
While I am at it, do I need to pull the engine out again to swap the heads (I used studs when Installed the heads)?
Lousy day :-(
89-91 Headers / Exhaust Manifold - Modified Ceramic Coated With AIR (ND) (corvettecentral.com)
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Pro
Joined: Jun 2018
Posts: 532
Likes: 104
I found a post about differences in the early and late L98 manifolds. Even though they look similar, the earlier manifolds are shaped differently and quite a bit bigger. Maybe the spark plugs would fit with the earlier manifolds.
exhaust manifold comparison - CorvetteForum - Chevrolet Corvette Forum Discussion
exhaust manifold comparison - CorvetteForum - Chevrolet Corvette Forum Discussion
Last edited by auburn2; May 28, 2024 at 10:20 PM.
Burning Brakes
Joined: Sep 2017
Posts: 938
Likes: 168
I found a post about differences in the early and late L98 manifolds. Even though they look similar, the earlier manifolds are shaped differently and quite a bit bigger. I wonder if the spark plugs would fit with the earlier manifolds.
exhaust manifold comparison - CorvetteForum - Chevrolet Corvette Forum Discussion
exhaust manifold comparison - CorvetteForum - Chevrolet Corvette Forum Discussion
this is what I'm talking about. at collector. it's one of the images. I only have 1984. 1.5" od tubing. calculate the area of pie shape and times it by 115 to get cfm.