My Bullitt! #9 Choosing right parts
Rebuilding the 390 FE engine – Choosing the right parts
It turns out the cylinder walls were in a pretty good shape and required only honig. That’s good news, since I can keep my pistons and just put a set of new rings on them. The current pistons are “high compression” giving 10:1 compression ratio, which is max I should go with the regular pump gas.
Read more about pistons here:
Heads are done and have new valves and hardened valve seats already installed.
Before putting them together I needed to decide if I should keep stock valve springs or not. Stock springs are good for up to .500 inch lift and there is a huge selection of camshafts under that value. After extensive research and talking to some friends and professional engine builders I started leaning towards putting a little more aggressive camshaft and harder valve springs. The camshaft is Erson E240222 with .551 lift and 220/228 duration at .050 lift.
This camshaft should give a little more horsepower and nicer sound without going to aggressive. The performance valve springs I will need to use now are PBM Performance 3100
When I was taking the engine apart I noticed that the chain was already a double roller performance chain. I checked the play and it was around 0.2 inch, which is “in spec”, but since I’m already here, I will get a new chain as well
During a couple of long hours spent on sandblasting all the parts
[Picture of parts]
I was debating about the headers. Yes, I would like to keep the original look, yes it’s already tight in the engine compartment, yes, I will have to modify the exhaust, but on the other hand – I will keep that car forever and knowing me, I will always be wondering why I didn’t do it right first time. In order to get something out of that engine headers is a must – gases need a smooth way out, but then it will need to breathe a little better too, so I need a performance intake manifold and a carburetor. And.. When I do all this, it would be very smart to put a stronger clutch in. So I started doing some research.
After doing some research about headers I learned that my options are quite limited. There is a lot of 390ci headers on the market, but I had some specific requirements. First of all, I started looking for “shorties” (shorter headers) to make sure there is no clearance issues, as I’ve seen a couple 67-68 mustangs with headers sticking out significantly on the bottom and I knew, I don’t want to scrape every speed bump on my way. Second – I didn’t want to have leakage issues at the header – exhaust connection, and I learned that there is a good solution on the market – JBA makes headers with a domed collector. And third – Need them to be ceramic coated to reduce the heat under the hood. I did not find the shorties for the big block unfortunately, but I found those:
Exactly what I need.
I also want to match it with this H-pipe:
and if I decide to add power steering some time later, JBA also has a drop down bracket, which will be necessary with those headers.
Time for an intake manifold. There is a lot of options out there when it come to improved intake manifolds. I wanted to stay with a single carburetor, I wanted a lightweight aluminum manifold. The first place I went to was Edelbrock website. I was thinking about the Performer manifold, but then noticed dual plane Performance RPM Series. I will have to give them a call, but I think this would be a better choice for my application.
Edelbock dyno tests a lot of their parts and you can check how they affect performance. The chart attached to Performer RPM intake for a 390ci engine looks like this:
I will have a very similar setup on my engine, without the RPM heads. My camshaft is also a little more streetable, so I may get few HPs and ft-lbs less than shown on the chart.
I was reading a lot about the carburetors. Again, too many options out there and way too many opinions. I knew I want to go with 750 CFM Holley, but after talking to few people I wasn’t sure. After I talked with my good friend, who is a really good mechanic, and had few Holleys before switched to Edelbrock I changed my mind. When I asked him what he thinks, he said” Do you have time? This will be a long chat… “ and before I answered… “Go with Edelbrock! That’s it!” Then he told me his experiences with Holleys. In short – Holley carburetors require a lot of adjustment but can give more power if tuned right. Since my mustang won’t be a “track car” Edelbrock will be much more user friendly. So that’s what I’m going with. I called Edelbrock and described what I’m planning to do the what I expect from the car and they gave me their recommendation – 650 CFM, electric choke and vacuum secondaries.
There is a couple details to notice when choosing the clutch. First – horsepower rating. You need to know how much HP more or less your engine will generate. Add 10% to it and here it is! You will also have to check the diameter of your current clutch if you want to keep your original flywheel. Another thing to check is the input shaft – its diameter and spline quantity. That’s how I made my selection: