Kenne Bell + Trick Flow heads Clearance Issues?

[SilverGT1]

I have a line on some new Trick Flow TFS-51910001-M-38 heads. I don’t need them right now but the price is so good that I am looking at getting them for a future build.

I have seen some threads that mention fitment issues with Kenne Bell but it is never an actual owner and never specific about the model the problem is supposed to be with. It’s always “I heard of someone on the board” but no real “I personally have this problem” proof.

I would be running these on a 2V motor with my Kenne Bell 2.1.

Can anyone here confirm with absolute certainty that these heads do, or do not, work with the 2.1?

Thanks!

 

[Blkkbgt]

Yes there are fitment issues with all Kenne bell intake manifolds and TFS heads. The good news is its relatively easy to fix. From what I recall following a few threads back in the day the issue is at the water passage at the front of the head. You can't really clearance the intake manifold so you have to grind on the head. Luckily TFS made this area very thick, thicker than the stock P.I. heads so cutting a little material off doesn't hurt anything. Honestly with some air tools or a grinder it's probably a 30 minute job of cutting and checking for fitment.

Modular head shop used to have a section on their site that had tons of very valuable information and one of them was the fitment issues with these heads and kenne bell manifolds. Unfortunately Jordan took them down when he took over MHS and Nick (RIP) passed away.

One thing to consider here is those heads you listed are 38cc chamber heads. The quick math tells me you're looking at about half a point bump in compression with any off the shelf piston. This is going to put you at 9.5-9.7 with the largest dish and depending on who you go with. It's something to consider when going forward with a build. You will be north of 10:1 if you put those heads on your stock short block.

One thing people don't know about those manifolds is that they have some minor fitment issues with later P.I. heads as well particularly the 9 thread spark plug later pieces. They have minor contact issues in the same area but 10 minutes with a small file and its taken care of.

Now TFS could have changed the heads a little since they last came out about 10 years ago but I know for a fact that it was an issue years ago.

 

[SilverGT1]

Thank you for the feedback. Yes, the 38cc would not be my first choice but the price is truly about half of list price. I thought I would be able to bring CR back down with the pistons. I wouldn’t be putting these on my stock short block. I started looking at parts for a build a couple of months ago and thought I could correct back that way.

I wasn’t really able to follow what you were saying about the later manifolds. My KB was purchased 2018 and my Mustang is a 2003. It’s all together and runs like a champ.

 

[Blkkbgt]

Thank you for the feedback. Yes, the 38cc would not be my first choice but the price is truly about half of list price. I thought I would be able to bring CR back down with the pistons. I wouldn’t be putting these on my stock short block. I started looking at parts for a build a couple of months ago and thought I could correct back that way.

I wasn’t really able to follow what you were saying about the later manifolds. My KB was purchased 2018 and my Mustang is a 2003. It’s all together and runs like a champ.

You might be able to bring the compression ratio down with custom pistons but I've never heard of anyone going that route with the 38cc heads. For all I know there is a maximum dish that can be used in a 4.6, I honestly don't know. A call to someone like diamond or gibtec may be a good idea.

What I was saying had nothing to do with the manifold but rather the later 9 thread spark plug hole heads like I have because ford changed the casting a little. They have fitment issues in the same area as the TFS heads but it is so minor I was able to file the manifold a little to make it work. I basically removed the casting flash and it was good.

Honestly if it were me I'd grab the heads and start building.