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Ok, I just bought a 72 Opel manta. 1.9 liter original motor. Last owner said he recurved the timing, re-jetted the carb, and milled the head .050, which I calculate to bump up compression to around 8.48.
This will become a daily driver shortly. I'd like to squeeze a few easy horses out of it. What are the good tips? I'm thinking intake porting and a better air cleaner assembly. Any easy carb swaps that work good?
Also the exhuast starts out dual then Y's into single. Would I get better performance going to full dual all the way back, or would that hurt more than help?
Cam options? where are they available? Aproxiamte cost?
Head porting? any tips here?
Any other little tricks?
I reliaze the motor is limited in power, but I'd like to get what I can out of it. And if I want more down the road I'll look into a motor sway, but I think I'm gonna try to keep it original.
 

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72skylark said:
Ok, I just bought a 72 Opel manta. 1.9 liter original motor. Last owner said he recurved the timing, re-jetted the carb, and milled the head .050, which I calculate to bump up compression to around 8.48.

*****Opel was optimistic with their factory compression ratings. You're closer to 8.1:1 with .050" milled off the head.

This will become a daily driver shortly. I'd like to squeeze a few easy horses out of it. What are the good tips? I'm thinking intake porting and a better air cleaner assembly. Any easy carb swaps that work good?

*****The most common swap is a 32/36 DGV Weber, or 38 DGAS Weber downdraft. They bolt to the stock intake, and easily adapt to the stock throttle linkage. Porting the intake is one of the best things you can do for power on an Opel.....

Also the exhuast starts out dual then Y's into single. Would I get better performance going to full dual all the way back, or would that hurt more than help?

*****Definitely keep the pipes merged into one. Running split downpipes will hurt power and torque drastically. Enlarge the main pipe to 2" however, and merge this into a 2.5" front muffler, 2.5" over axle pipe, and 2.5" rear muffler. Power and torque will improve substantially over stock.

Cam options? where are they available? Aproxiamte cost?

*****Tons of options for regrinds. However, with stock valve springs, you're limited to .430" lift. And the stock rocker arms and retainers tend to fly apart above 7800 rpms with high lift cams anyway.

Head porting? any tips here?

*****Stock valves? Then leave it alone, you'll do more damage than good. Opel heads are tricky to port correctly, and don't respond well to porting with stock valves.

Any other little tricks?

*****Turbos are fun......

Bob
 
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