How much added horsepower can you expect by adding intercoolers to a blown 540. Nothing crazy putting out about 750 hp currently

75 to 100 with the correct tuneup.

What you gain from an intercooler is lower air temps and less change to detonate the motor. You can then add more boost, then you get the HP increase. On my old boat I changed the intercooler to an rtech and had to increase the amount of fuel in the efi map by 15%, not sure how much more HP that was.

Yes If you dont change the tune, more like you will not lose as much HP from heat.

Skydog

What you are asking for is a bit of a moving target. It will really depend on what your intake trac temps were now and if now getting pretty high, what the planned intercoolers will bring them down to under full boost and load. The cooler air charge temps will allow a bit more timing and should allow some more boost from driving the supercharger harder.
The actual amount of increased HP will depend on what temps your air charge is at now under full boost and what boost levels you are running and what supercharger type and size you are using. With this info I am sure some of the supercharger experts on here can give you a closer estimate.

Best Regards,
Ray @ Raylar

Depending on the boost level you are at now is going to determine the need for a intercooler if you are increasing boost. Aluminum heads or cast iron will make a difference also. Do you have a 8-71, or 10-71, the amount of blower speed will effect the induction level of heat. Its going to take about 1.5 more psi to move the air through the intercooler which will increase loss of output power taken up by the supercharger
Here's a little example; 588 cid, merlin cast iron heads, 10-71 with 6.5 boost, timing 30 degrees, 4150 carbs. 925hp @ 6200. tested a intercooler TBS, only picked up 35, boost being the same. I would say, all the same it took more to push the air then the output power was worth in is situation.
This was a test with another 588, 14-71, AFR 355 , TBS intercooler that had a cooper nickle core, this core was a protype from KEPP, 7 psi boost. The engine only made 1015hp @ 6300. Something was WRONG! Called THE BLOWER SHOP, explained cooler core to them. I had no idea about this crappy core. TBS send me 2 reg cores and one copper nickle, to test for them. I first installed the copper core. Power up 125hp, we also measured inlet and outlet air temps, big drop compared to old core. Same test for aluminum core, power was the same and air temps about the same.
Type of intercooler and application are going to be you main concerns. Is the trade off in what you have staying the same or are you going to change heads, cam and increase your blower speed. Just bolting on a intercooler is most likely not going to be cost effective unless you are building this engine over again with the intercooler, being including into build and the final results you are looking for.
The Blower Shop, has air temps results from the test we did, if you decide between alum. or copper nickle core. The copper nickle will take more inlet heat before it melts, but is mostly for salt water conditions. Alum cores are good for about 3-4 yrs, depending on whether, you flush the engine and cooler with a neutralizer as Salt Away, or something like it.
Hope this helps you, Mark

Great input and expeirence results and recommendations here Mark. I knew one of you guys with good intercooler expierence would give some great info and direction.
I think with this type of input, information and specifications will start to make more sense for a good decision on whether to add an intercooler from a dollar versus benefit basis and help answer the question how much more power?

Best Regards,
Ray @ Raylar

Thanks Ray! Sometimes I see, questions answered with just something off the top of the persons head or just an opinion. We all should work from data gained by our own experience or facts of information given the manufacturer.
I know a lot of us are busy right now with little time to spare on the forum. I felt I needed to take the little extra time to explain this before the guy went out and spent money, with low results.

Ray, Mark and Turbojack hit the nail on the head.

I might also add that the restrictiveness of the core matters less on a positive displacement blower and is more important on a non-positive displacement induction (turbo or centrifugal).

Thanks guys that really help alot and help me/us to understand what really is going on there. Thanks again