I am looking at changing cams in my 502 EFI"S,they are currently hyd flat tappet and I would like to go hyd roller.There are a few HP 500 cams in the swap shop,and I was wondering if I can use these with EFI set ups even though they are for carbs.

I was just reading a similar thread yesterday I think. Look back a little on Q&A. Hopefully this will answer your question. There was even a quote from Bob M. in the thread.

Good luck,
JOhn

Thanks John,I actually found alot of threads that touched on this a little.It seems that by the time you change cams,springs,push rods,lifters,and reprogram your ECMs its a pretty costly job.And from what I gather,its a very minimal gain.I already have Stainless Marine exhaust and some Crane roller rockers.So,how much more could I gain with say a 731 roller over my stock hyd flat tappet.Any bodys thoughts?Thanks

Did you notice any gains from the stainless marine exhaust and roller rockers??

The ECMs are what I am not familiar with however If you were to change cams I would go with the 741 and bump comp to 9.5 to 1. I would think the gains would be 75 + easy. Then again I have no clue when it comes to reprograming the ECMs. Regardless your still looking at some bucks. By the time you get the heads machined down and new valves, springs, grind, etc your looking at probably around 2,500 plus.

Head work 1,200.00 valves, spgs, machining, etc
hyd. roller cam 350.00
timing chain/gears 100.00
timing chain cover 150.00
roller lifters 500.00
roller rockers 300.00
pushrods 100.00
gaskets 150.00
Reprograming ????

As always things always turn out to be more than expected. Good example is your heads. For instance you would want to update you valves with good inconels or similar and so on. Definately read as much as you can before pulling the trigger. I remember when 3k did a complete engine.

Call Bob M, He'll give you the low down on what can be done and what you will get. I've been very impressed with his honesty! If you need his number let me know and I'll send it to you.

Mild Thunder,as far as gains I really don"t know, I bought my boat complete less motors and haven't had it on the water yet(sucks for me).John the 502's I have are basically running take outs (approx.350 hrs) ,the heads on both are fresh and already have upgraded valves.I had the SM's and the roller rockers already.I was trying to get as close to 500 horse as I could with cams,rockers,exhaust and a little wishful thinking.

I realized you had the rockers after I posted. As mentioned call one of the experts in regards to the programing. I know that cam with a bump in comp and your cubs would be easy to get over 535 hp. Give Raylar a pm. He responds pretty quickly and will fill you in on the ECMs.