0 Members and 1 Guest are viewing this topic.
I'm sick of searching for a set of headers for my Bobcat, it's frustrating knowing that my exhaust is still restricted by the heat shield. I recently purchased and applied some goodies for her, clearly a header would just knock my socks off if I could put one on. As far as I'm concerned, the 2.8l came from the factory in Germany and people tear them out of mustang II's for 400 horsepower builds. I've heard of 1 individual that salvaged an engine from a stang and swapped it into an old cougar, sick results. Where are the headers someone please tell me?
So your opoiun is that headers on a 2.8 actually robs horse power? What about putting on a 4 barrel intake and a holey 390? Have heard that Aerostar vans with the 2.8 have sorta header type manifolds that might work, just looking to dump some poundage with the exhaust manifolds. Would really like to beef this 2.8 up some. Any advice would be awsome.Thanks, Tink
Chris, Nothing like getting tested. Well I started it so here goes. This is from my experience, never mind that I am a thermodynamic engineer and work on ProEngineer with FloEFD thermal software. The 2.3 is a different beast than the 2.8. The 2.3's displacement is pretty big for a 4 cylinder globally speaking. I have a fiat with a 850 CC 4 cyl so you can see what I'm talking about. It also has a greater stroke and higher capacity of air that needs to be removed where the 2.8 has a large bore but a tiny stroke (which give it the ability so wind up like an formula one car, relativly speaking) and has smaller bursts of air. Now the 2.3's exhaust manifold is an excellent unit. The ports are a bit tiny BUT it is essentially a cast header (unlike the 2.0). The 2.8 manifolds are not bad but certainly nothing like the 2.3's swooping shape. Onto the 2.3 head work. Here is what I have done to my Pangra's in term motor (until i finish its 2.3 turbo).It is a 74 block with a 79 head. I donít know if there are any differences but I am just stating the facts. I popped in zero deck pistons in the block and milled the head by 120 thou. This made the chamber 52 (I think) CC + the felpro gasket which was 12 CC. Then I clayed the valves to make sure there was clearance (i calculated it before but I wanted to make sure before I ruined everything). This bumped up the compression to 10.9 on paper but 10.6 in reality. Originally it was just under 7.0:1. Then I bought a basic stage one cam from Esslinger. More lift and duration(i forget the numbers). It is nothing radical but i just wanted something better. I did not do any porting since I ate so much off the head already. When you mill the head, you have changed the geometry of the timing belt. This means that you need an adjustable cam pulley. Mine is advanced 4 degrees. Once done, I knew that the stock HP at the flywheel was around 79 or so in 1974. When I had the stock autolite tuned (at a smog shop) and the distributor curved, the car had 105 hp at the rear wheels! That means about 130 at the flywheel! This all cost me about $400. By the way, I installed a cat on it (because they are good for the environment, period) and its CO2 output was nearly unreadable and the HC was at 18 ppm. Legal (if this car needed a smog which it does not) is 250 ppm. A header would probably bump up the hp another 3-5 hp but this car has A/C so I do not want further heat loading. Once the motor needs more fuel, then I would say holley 350. I really stay away from 4bbls unless you have serious engine work and a monster cam. Then you are in the 200 hp range and the car is almost unstreetable. So yea, milling the head is ok but different pistons is the right way. I take it easy with my stuff so it was fine for me. You donít need to rebuild the bottom end unless its history us unknown. Best bang? Mill the head, tune the carb perfectly and curve the distributor. I have since ditched the points for an MSD unit (which I hate but gave the car noticeable gain in power), accel 8.8 mm plug wires, and a few other bits. Moral of the story is, make your car run cleaner, more efficiently and tune it perfectly. Just doing that you will see massive increases in power. Headers, carbs, intakes are all things you get to AFTER you do the hard stuff. Here's how you know if you did it right: You will get more power, better mileage and your car wonít stink like raw fuel like 90% of cars at car shows. A lot of info there, hope I answered everything. Back to work I go. Alberto: I never had an opportunity to thank you for your inputs. That was very helpful information and a good roadmap to begin with. I really appreciate you taking the time to share your experience here!Chris