TR6 TR6 Intake Manifolds

[71tr]

Besides the outright appearance what are the differences between the early TR6 intake manifolds and the later style? Can a later style manifold be used on an early ('71) engine?

 

[kodanja]

they wont line up with the ports...

 

[swift6]

The intake ports are spaced differently between early and late TR6's. The exhaust ports are the same though. The longer manifold is also supposed to yield a better torque curve.

The manifold changes (intake and exhaust) were attempts at maintaining the HP and Torque levels of the early cars while they were reducing compression and adding other items to maintain/reduce emissions numbers.

 

[glemon]

So if you are building an engine to go a little better is the later head and manifolds a better option?

 

[TR6oldtimer]

So if you are building an engine to go a little better is the later head and manifolds a better option?

Yes, and include the two pipe exhaust manifold.

 

[71tr]

thanks for the responses, i asked because i like the looks of the later intake manifold....nice long curves!

 

[John_Mc]

So if you are building an engine to go a little better is the later head and manifolds a better option?

Yes, and include the two pipe exhaust manifold.

I have a '71 which I've been told has the HC engine and the earlier manifold. So, if I could hypnotize the wife into believing I need a triple carb set-up or other spiced-up engine mods, would I be wise to seek out a later head, or are there mods that can be made specific to the earlier head with good results?

 

[Guest]

Hi John,
If you have the early head, consider having it shaved, ported and polished by a good machine shop, with reworked valves and springs, put in an aggressive cam, shorter chromoly pushrods and use the stock early intake manifold to hold some bigger SU carbs, reworked to new condition, of course. Cheaper than trips and, IMHO, prolly as good. You can buy SU carbs brand new, or get a good set reworked. I used Gary Martin in South Dakota to bring my carbs to concours condition. He can source you a nice set cheaper than new, and will be in better shape than new when done.

 

[Trick6]

It helps to have the Hi Compression no matter the head. Now are the valves larger and are there internal casting improvements to enhance the breathing? I went down this head conversation before and came away learning that there are a bunch of different heads. So there is much more to it then "early" and "late." I think you should start thinking "close intake spacing" and "wide" instead of early and late. I am running a close space head with 44 cc combustion chambers yielding about 9.98:1 compression ratio. I have another close intake spacing head with very low compression (just in case I want to go to the supercharger)in the shop corner.
I suggest that you keep the head you have and get the two pipe exhaust manifold. And if you are getting the GoodParts tri carb setup, consider the SUs because there are many more metering needles to choose from to aid in your tuning. I have the 3x175s narrow intake spacing and had a big challenge in getting the jetting lean. You need to do some research and decide what you want for performance, dependability, and maintenance. I hear that the Keihin or Mikuni carbs come just right (https://www.prirace.com/) and don't require a lot of fiddling with. I looked at some Keihin CV carbs that people are very high on.
There was an excellent post maybe four weeks ago discussing the various TR6 heads. Maybe someone can find it and reference it for you.

 

[Soulcharger]

Hi, I need a carb manifold, part nr 308088 where should I start looking ? Thanks, Chris

 

[Marvin Gruber]

Chris,
what manifold or should I ask what car did that manifold come off of? I have several early and late TR6. Pictured one does not look like a std early TR6 manifold. As far as which head to use, I would go with the early big valve. The later twin exhaust pipe manifold will work on it. Later intake manifold can be made to work with some mods.

Marv

 

[Soulcharger]

Chris,
what manifold or should I ask what car did that manifold come off of? I have several early and late TR6. Pictured one does not look like a std early TR6 manifold. As far as which head to use, I would go with the early big valve. The later twin exhaust pipe manifold will work on it. Later intake manifold can be made to work with some mods.

Marv

Hi Marv
The photo is an early 250/6 carb manifold, just the one I'm looking for. I bought a recon engine and it has the early small port head, I have a later model manifold so it doesn't fit. The part number I need is 308088.
Chris

 

[glemon]

Hey Marvin, I am interested in what you said about making the later manifold fit, which I considered, is it just a matter of hogging out the manifold and head a little bit to line up the ports? I think they are only off by 1/4" or so if I recall.

 

[Marvin Gruber]

Chris,I just built two TR 250 engines, neither intake manifolds were like the one you have pictured. The oval setup that's on there has me puzzled. Mounting flanges are different as well. Wonder if that it is a PI manifold. I have spare early intake manifolds but out of town until Oct 10 if you don't find one by then.

Glemon, just port out the later intake some, unless you're racing the car that little offset won't effect it. Have done it several times with no problems. Use the early intake gasket.

marv