Thread: pre '86 SBC 350 Conversion to EFI and cam selection

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Originally Posted by jerry clayton

You won't find many mechanical HIGH pressure fuel pumps for street applications-----

Jerry,
Edelbrock has the answer for those who have a low pressure system in their under hood universal sump-https://www.edelbrock.com/adjustable-universal-efi-sump-fuel-kit-67gph-35-90-psi-36031.html

so, I was talking with my Dad, and he said it would be better if the camshaft matched the heads. In what ways is this necessary and in what ways is it not?

Well, your father is right! (You know what they say, “Father knows best….)

Reading through this thread I have to say that Jerry Clayton’s idea of a late model engine/transmission pull out from a wrecking yard sound like the best and certainly the most cost efficient way to go for you right now. If you’re going to build what you have we need to make the assumption that the short block can seal the cylinder pressure which (as I mentioned in my first post) is questionable on a 40 year old engine. If they are tight, the two most critical components to making horse power and torque are cylinder heads and a camshaft that offers proper valve timing that can take full advantage of what the heads can deliver in terms of air flow. Remember that the internal combustion engine is just a giant air pump and the more efficiently air is moved into and out of the engine the greater the power it will generate.

Building a full tilt race engine is, in some ways, easier than a street engine as the race engine builder typically has a large bucket of money (or sponsors with deep pockets) and is building the engine to run at extremely high RPMs for a very short period of time. A dragster reaches more than 300 miles per hour in seconds and they typically redline around 9,500 RPM. Those engines turn 5-600 revolutions from light to light and including a burnout, and only need to survive about 900 revolutions under load. You’ve maybe seen the instances where between races a pit crew under the guidance of the chief mechanic will completely tear down an engine and replace parts that cost tens of thousands of dollars. Well, we don’t do that on street engines so the components must be able to harmonize and run for a long time from idle to 5,500 RPM with the bulk of their operations in the 1,500-3,000 RPM range. As such, camshafts for acceptable street performance need to take full advantage of the heads over a wide range – not just at WOT. So your father’s assertion of matching cam to head is a good one.

In my opinion, improper cam selection is by far the most common mistake made by novice builders. They all seem to want that “rump-rump” sound thinking it is a sign of a mighty powerful engine when in reality, for street applications it is a disaster and they are spewing raw fuel out the exhaust for 75% of the time as the engine will not see the 6,000 RPMs necessary to take advantage of the aggressive cam profile. Big cams also require different springs and more often than not, machine work on the heads to prevent binding of the valve springs of worse yet, improper valve-to-piston clearance (which will instantly trash an engine).

Also in my opinion, the cam selection for the Edelbrock system would best be decided by their (Edelbrock) tech team. They have a lot of expertice in this arena and in my experience, are some of the nicest and most professional people to talk with. An hour on the phone is not a problem with them and they seem to really want to be a part of your project – even if you are using one of their products in conjunction with another brand, i.e., Edelbrock carburetor on a Weiand manifold. I’ve had them send me an entire jet/metering rod replacement kit as a “demo” after talking with one of their tech people. Not saying that always happens – but I really like the support from Edelbrock.

Edelbrock is also an excellent choice for heads and they are comparable price wise to the AFR 195 that I mentioned early. The problem is availability as Edelbrock parts are not in stock anywhere right now due in no small part to the closing of their California operation and moving to Mississippi to share space with Comp Cams.

The new Pro-Flo 4 EFI now comes with a tablet computer for dynamic tuning that seems to make it a real good fit for aftermarket application. That said, Edelbrock is making the assumption that you are starting with a healthy engine in terms of short block seal (rings) and top-end components (valves) to support the optimum performance of their product. I have not installed a Pro-Flo 4 but in what I have read it sounds like a winner – again, the availability right now is limited.

Ok – all that said, I think that a pullout is your best bet for now. Looks like there are some good wrecking yards in the Oklahoma City area and this would be a nearly bolt-in solution to give you great performance for a long time. You could then rebuild current engine over time and make it exactly as you’d like - after vetting the block.

Hope this helps - I know when I was 21 money was always an issue and my dreams often outpaced my wallet but I would encourage you to take this slow and recognize there are not many in your age group like you who are wanting and willing to tackle a project such as this. You are to be commended!

I really like the looks of the 1980 C-10 and hope you keep her for a long time.

Regards,
Glenn

Glenn's advice to grab a takeout package for now, and then have more time to build your existing engine the way you want it is a good idea if you need to have the truck for your daily driver, but regardless calling the TechLine at Edelbrock to get their advice on the cam selection and compression ratio is solid. With your description of how you plan to use the truck, and what you'd like to have from it they can give you good advice on the cam. You'll need to tell them what rear gears you plan to run, the diameter of the tires and your tranny gearing to pick the right "sweet spot" for cruise while giving good power.
When I was working with my ProFlo XT I spent hours on the phone with their guys, and we even had the ECM on line in shared mode so they could see what was happening - in fact that identified a problem when they were watching the system voltage during crank, and pointed out a wiring problem I had. Good guys, and like Glenn they sent me a "demo" fuel pressure regulator when we determined mine had ruptured.