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How big of a issue is a step up with a smaller intake with significantly larger head ports?
(This is on a roller cam 96 351w long block/e40d with 93 ecu and accessories in a 93 bronco)
I decided to follow the advice of many of one of my previous posts and sold my GT40P heads as well as some funky bbk headers I had sourced for 750, (somehow came out ahead on that deal lmao). I was initially planning to buy the LMR 170cc sve heads, but they were sold out so I ended up getting these funky Chinese vevor 175cc aluminum heads after one of my friends who runs them on a 302 fox recommended them,
Weirdly enough the castings were decent and they fit well, so I guess we'll see how they hold up over the next year or so,
However they have larger ports than the stock E7 heads by far, about 2.100 x 1.280 on the intake side of things best I can tell according to the intake gasket used, the stock efi truck intake is significantly smaller do there's a pretty bad step up, I know the reverse is bad but how bad is this? My guess is its reducing velocity pretty bad and maybe creating a low pressure zone that FUBARS atomization?
I also converted to 1.7 ratio SpeedMaster roller rockers at the same time, despite this the truck actually seems slower below 3000 rpm or so, at which point It seems better than before?
Im planning to go through and do a mild cam and the edelbrock efi intake once I'm back for summer, does anyone know if the Edelbrock ports are any bigger? Or if there's enough material to match them? They don't list the size on Edelbrocks website.
My only other guess for the poor performance would be the ECU throwing a fit as I know the Speed density can be funky at times, anyone here have other ideas?
Does anyone here use the Edelbrock efi truck manifolds? I'm looking at the 3881 model at the moment and I'm wondering if anyone's been able to gasket match it large enough for fel pro 1262 gaskets.
This is the 1262 Gasket over the new mystery Chinese heads This is a 1262 Gasket over the stock 93 truck intake that I've heard is notorious for poor flow
You will usually find the Edelbrock 3881 listed as 1.85" x 1.04", but I measured mine at 1.86" x 1.10" before porting. The correct gasket for that intake unported will be the Felpro 1250, but do yourself a favor and buy the 1250-S3. The steel core gaskets don't have the tendency to come apart like the composites. Unless you are planning on porting the intake manifold, you don't need the 1262 gasket, you only need to be slightly larger than the manifold ports. If you do port it, then get the 1262-S3.
This is the pic of the 1262 gasket to the Edelbrock intake manifold. Not certain it will help.
That's a huge help actually! Looks like there should be enough material to match to the gasket, and even if not It will be a hell of a lot better than what I'm running now. Thanks!
Do you know what those heads flow? Given the lack of published numbers, they probably wouldn't produce spectacular numbers, but I'm sure that they could use a better intake than the stock ~177 cfm. Unfortunately, you are looking at making a couple of mistakes that you will probably end up regretting. Firstly, grinding a bell mouth in an intake's port exits will gain you nothing, and not knowing the flow of the heads, you don't know if you would even gain much from a full port job. Secondly, go look at some of the stories over on Corral of the composite Felpro Printoseal gaskets coming apart. Everyone who has issues with them end up with the -S3 steel laminate gaskets. Using the larger 1262 gasket will probably only increase the odds that the gasket will fail. Also, if you do decide that you need to grind on the intake, don't just use the gasket as a template. Things don't always line up like you think they should. Had I laid the 1262-S3 gaskets on my intake for a template, my intake manifold and head ports would have been almost 1/8 inch off from each other. AFR doesn't put their ports exactly in the stock location.
I am using some Cometic intake gaskets that were custom made. I bought two sets. They are metal reinforced.
I am pretty much stuck using my stock Ford 351W lower intake manifold. I purchased the use Edelbrock manifold just to see if I could 'butcher' it up enough to work. I don't think it will so the stock manifold will have to do. I honestly feel I can open up the stock ports on my factory manifold. I think I can also practice my cast aluminum welding skills [I don't have any at this time] to fix any damage I may run into.
If all you do is open up just the gasket area, it probably won't do much, but with a bit more time, I don't think you will do any harm if you open up the entire port. Without a doubt, if you got an Edelbrock manifold, their ports are much larger and can only help you.
The secret to the heavy aluminum parts is getting a good preheat. I would usually get a good carburizing flame going on the oxyacetylene torch and use it to smoke up the weld zone, then start heating from outside of the weld zone and work in slowly until the smoke disappeared. Just don't get the flame to close. That should put the preheat at about a 800°F if you do it properly. Even putting the parts in an oven at max temperature would be better than nothing, or you could use a combination of the two methods.
Buy a set of aluminum grinding burs and give it a shot. It can't be much worse than fitting up a set of custom made headers.
Buy a set of aluminum grinding burs and give it a shot. It can't be much worse than fitting up a set of custom made headers.
Obviously, you have not seen my tig welding skills.
My goal is not to get that thin. But if I do, I can only assume the thin casting [where I will be welding] will not need that much heat. This part of the project has not started so I just think about the task at hand. My issue is cleaning this manifold so it looks like I could weld on it, assuming I have too. Because of the supercharger and it's use is for towing, I am not looking at the largest port possible. Just trying to keep the same size through out the port.
Obviously, you have not seen my tig welding skills.
My goal is not to get that thin. But if I do, I can only assume the thin casting [where I will be welding] will not need that much heat. This part of the project has not started so I just think about the task at hand. My issue is cleaning this manifold so it looks like I could weld on it, assuming I have too. Because of the supercharger and it's use is for towing, I am not looking at the largest port possible. Just trying to keep the same size through out the port.
Just keep in mind that flow losses come from expansions, not contractions in the port.
