I had built a TC88 a couple of years ago to 95" for my Mukuni carbed FXDWG3, TW9BG roller woods cams, yada, yada. I had the TC88 heads ported, polished, CC'd heads, 3 angle seats, Manley stainless 1.94 valves, 1.6 exhaust, and springs. The combo made an awesome 113hp / 111 TQ. I decided to have another set of heads done with the same combustion chamber mods and install 2" intake valves and 1.6 exhaust....HP went up by 4, TQ by 2.

Now I have these "old" 1.94 TC88 heads that I have modified to accept the front upper motor mount for my fuel injected 08' FLHX for a 103 or 107 build.

Question, have the TC96 heads improved that much that I should have them reworked like the heads that I have or just freshen' up the TC88 heads and install them on my build? I'm not looking for the last ounce of HP or TQ for this build...looking for opinions and if I'm missing anything. Somewhere I read the intake flanges are different ?? Thanks guys.

 

The TC96 heads are an improvement over the TC88 heads but do not compare with a set of ported heads. TC88 heads will bolt on a TC96 and visa versa; no issues there. Compression is one issue you need to consider. The larger bore of a 103"/107" engine will increase compression and maybe more than you want/need. You need to know your chamber volume and run the compression calcs based on the cams you intend to run in the larger engine. You have some options but need to know the numbers.

If they will work, the other issue is the possibility of the larger intake valve kissing the top of the OEM flat top piston. The valve reliefs are for the smaller intake valve and with higher lift cams, it is possible for contact. The valve reliefs are deep enough but may need to be opened up and moved outboard. See the photos.

 

Good thread. Be sure to tell us what you end up doing.

 

DJL, appreciate your reply. I will calculate the compression ratio, check clearances on the "new" pistons as I had done before on my other build. I realize the the modified TC88 head is much better than the "stock" TC96 head....my question is SHOULD I have the TC96 heads done like the TC88 heads that I have??? Is there any real numbers to gain that say most definitely or .....am I only going to gain 5 HP / TQ and invest $800 in another set of heads? My first thought is use what I have as they produced great numbers before.

 

You won't gain anything by working the TC96 heads unless you want two sets of similarly ported heads. Once they are worked, it doesn't matter which core you start with. I would run the ported TC88 heads if the new corrected and cranking compression is manageable.

 

Once the headwork is established, there is not a difference, on the intake side here.
We do, however, create a "raised floor" exhaust port on the early heads, that does pick that up a bit, vs the later casting port.
Scott