I have a set of 1.94/ 1.5 heads that have new back cut valves and mild porting. The flow #s are:

.100- 64 int 56 exh
.200-134 109
.300-179 140
.400-204 160
.500-205 165
.550-207 166

I plan on getting a hotcam, and I have all the other mods. Do these flow good enough or should I get some more work done to them. I don`t want to go through the hassle of putting them on if they are not going to help much.
I also have a stock bottom end, m6 and 4.10`s.

Kevin

 

There are several things that effect CFM and flow #'s. Not all benche are the same and some people might not check flow at 28" of depression.

The reason that I am saying this is because those intake #'s are pretty close to a stock LT1 on by bench at 28". A stock LT1 flows about 213 or so on my bench and the exhaust flows about 145 or so. Some benches flow low on the intake and high on the exhaust when compared to a Superflow bench.

Regardless of what OTHER benches say heads flow, you have flow #'s from 1 bench. If you could ask the person with the flow bench what they flowed on intake/exhaust BEFORE and portwork or valve job work and look at the gain in cfm, that would be a better judge of comparing flow #'s. If they did not flow YOUR heads just ask what a stock LT1 usually flows for a reference.

"IF" it is a Superflow bench and the #'s are corretc it seems that they did something wrong and lost CFM or they were tested at somethinh other than 28". The .100 lift #'s are either 28" #'s or there was a slight leak while testing or like I said, it is a Flow Data, or someother bench.

The exhaust flow #'s are usually not as close to the intake #'s as those so that makes me think that it is a diff. bench or they were MUCH more succesful with the exhaust porting as compared to the intake.

NightTrain66


Just looking at the

 

Nighttrain,
The heads were flowed before and here are the #s:
.100- 66 int 53 exh
.200-125 98
.300-168 127
.400-191 145
.500-195 150
.550- 198 151

It was at a test pressure of 28'' and a bore of 4.020
I don`t want to waste my time putting these on if they won`t help or are screwed up. I am shooting for a 12.00 car and I only drive it for fun, so I really want to do what it takes to get it to run there. I don`t need crazy heads, but just some that"work"

Tyhanks for your input
Kevin

 

I would try and get some more out of them or start with some other heads (depending on what they did to yours). There should be more "easily obtained" cfm in them.

That equates to about a 230 cfm head if a stock LT1 flows about 215 or so. Most people are able to get 245 with stock valves and basic porting. I would try to get them to do more to them or find someone else.

Is that their "full-port" or is it just a $100 "quickie" job?

If you are doing them yourself you could learn some tricks from someones DIY porting page that they have on here. If you follow their guide lines you should have better results than those. That page has flow #'s posted as well but the flow bench they use has stock flow #'s that are higher than my bench says, especially on the exhaust. You can not compare the overall #'s but you could look at the cfm gain. I think that they picked up about the same on the exhaust as you but they picked up more on the exhaust side. Either way, you could at least look and see what the port should/could look like and compare to yours to see if the porter did much to yours.

You could do a search on "DIY porting" or "porting tips" or "porting help" and find that page or other posts and get some info that others have posted when asked for porting tips.

good luck


NightTrain66

 

Thanks for the info, I think I will try something different. Could you e-mail me and let me know what you would charge to get a set of stock heads to flow.