Hey fellow members I got a question. Does anybody on here run a built motor/ stroked 2.1-2.3 and have a cast manifold.

I'm asking because when I had a stock block with my hta86 cast manifold I put down over 500awhp. Now that I'm built at 2.1l I can't pass 500. I'm getting valve float n it seems like a ****load of backpressure. Is going tubular that much better? I checked the archives n the only car I saw that went pass 600 was sumans beast. Every other car had 440-580awhp on the stock block. Didn't see anyone with a built or stroked motor with a cast Mani Going over 600hp. Just want to get your opinions on the cast manifold, can it be really that restrictive on a stroked motor.
I was looking for 600+awhp on pump n meth was I mistaken. I was told to go out n get a tubular n that will solve my issue which Im going to do Just wanted to hear your comment an so if someone has the same issue I have they can search n find an answer.

Also my motor is strong as ****, its built out the *** to hold up to 800awhp. Thanx for all info I receive.

 

Not much info on the supporting mods. What are you using for a fuel system?

 

Single walboro 255 with 1000cc injectors. Hks 280cams.

 

Your cams are part of your problem.

 

HKS 280 cams suck.. Set of gsc S2 would help the car out.. But yes the cast mani is restrictive..

Mike

 

When I was on the fs635, Dave Buschur told me the cast manifold was a restriction. The hta86 is even bigger than the fs635...so I'd say definitely go tubular.

 

how do you know your getting valve float? Did you measure the backpressure, or why do you think you have excessive backpresure? What do you have for an exhaust system? Could you possibly have a boost leak?

 

At 30psi when on the dyno after a pull the car can't idle correctly for about 5-10sec. At 25psi after a pull it idles perfectly. Just putting in my hypothesis, like the backpressure is keeping the valves open. Don't know if that makes sense.
But why I'm confused is that I made 534awhp with the same kit before I blew up the stock motor(cams,meth ems) then all that is new is a built 2.1l llongblock n its not passing 500aw.

I really thought the cams were good since they're HKS.