Getting rid of the outer 4 "kinked" runners - 4 intake manifold bolts are deleted with this modification.
I did not really undertake this project to increase engine power. I did it more for flow equalization between cylinders, and to help get more even mixture motion (swirl and tumble) in all 8 cylinders. Having more mixture motion in some cylinders creates faster and slower burning cylinders. Faster burning cylinders will detonate before the slower burning ones.
In theory, the modifications to the intake I made should help reduce the chance for detonation, and make the engine more tunable by evening out the fuel and air distribution to the cylinders.
Step 1: To the left is the stock Edelbrock Torker intake fresh from the machine shop baking and shot blasting. Notice the 4 areas circled with magic marker – those are the areas I instructed the welding shop to fill. Also notice there are 12 holes (6 per bank) for the intake fastening bolts. See how the runner must neck down at the top to allow 4 of the bolts to be installed?
Click to enlarge.
Step 2: The intake is pre-heated, and TIG welded while hot. The intake is also post-heated, to bring it’s temperature down slowly. All of these steps are taken to minimize thermal shock on the intake and the chance for cracking. The welding work was done at East End Welding in Akron, OH, and the cost of the welding was under $100, but they may have given me a discount because I have taken a lot of work to them in the past.
Click to enlarge.
Step 3: Next comes the porting. First the intake was ported internally. The only major work that was done internally was to remove the “kink” from the 4 outer runners. The picture below shows the runner with the bulge removed. I only wish I had this same picture before porting, but the earlier picture looking down from the plenum shows the restriction that is now gone. After the internal porting was finished, the external cosmetic work was performed. I made sure that when I had the intake welded, I had enough material added to smooth the outer shape such that the final result would be what looked like an untouched intake manifold. The last step was one more trip to the machine shop to have both intake surfaces milled for flatness. So far, nobody has looked at the intake on the car and asked me about the modifications.
Click HERE for a view of the finished result, on the engine.
I did all of these modifications before installing the intake manifold, so I cannot say if there was any ET improvement from these mods alone. I have not had any problems with the intake manifold sealing with only 8 bolts holding it on.