Originally posted by: vi_edit
From real world experience in non-sports cars, DOHC engines have better highway speed passing power than a pushrod of equal stats.
Go hop in a GM 3.4L OHC or the Ford 3.0L OHC get behind a car doing 55 MPH and try puching it to pass them. It's hopeless. In my 30 valve 2.8L Passat or a 3.0L Nissan VQ the results are much different. They get up and run much better than the shortwinded OHC engines.
The DOHC 3.4L in my old Monte Carlo was also better at passing than the 3800 series that's in there right now.
But, the 3800 gets better milage and is indeed cheaper to work on.
Each has it's merits.
You shouldn't make that kind of comparison.
DOHC is meaningless if the car makes 120 hp and the pushrod 4 banger makes 200hp. Guess who's got better highway passing power.
If both engines in question are the same # cylinders, displacement, horsepower and torque then all things being equall they will perform the same.
The difference might be some negligable fuel economy differences.
Common you guys! This is a stupid arguement.
As for pushrod engines don't rev: be specific about application and the engine/car in question. Blanket statements are stupid statements. Take the stock 426 Hemi. Here is an engine with extremely heavy reciprocating mass and a very stiff valvetrain and 12.5 compression. 7500 rpm stock is normal. Modified they rev like no tommorrow. Pushrods are still used in drag racing. Top Fuel hemi 8000 hp and what? 12,000 rpm?
Pushrods are a weak link but, in everyday real world applications no one notices the difference. Fuel economy difference is barely even noticable. Add a roller cam and lifters and there is no detectible difference.