Twin cam intake manifold question
Thread Starter
|
Intermediate
Joined: Oct 2024
Posts: 32
Likes: 29
From: Missouri
Twin cam intake manifold question
So ive searched this and haven't found exactly what I'm looking for.
I have In 04 Heritage I'm gathering parts for to put an big bore kit on.
I have a set of cylinders and heads from an 07 with about 17000 miles on them that I plan on sending off to Hammer performance sometime in the future.
It is my understanding that they will be direct bolt on to my 88 engine with the exception of needing different intake manifold flanges. Can i just buy any flanges made for the 06 and up 96 engines or will the fact that my bike is carbed require something special?
everything ive read says the manifolds are the same but doesnt state if this holds true between carbed and efi versions.
Thanks
I have In 04 Heritage I'm gathering parts for to put an big bore kit on.
I have a set of cylinders and heads from an 07 with about 17000 miles on them that I plan on sending off to Hammer performance sometime in the future.
It is my understanding that they will be direct bolt on to my 88 engine with the exception of needing different intake manifold flanges. Can i just buy any flanges made for the 06 and up 96 engines or will the fact that my bike is carbed require something special?
everything ive read says the manifolds are the same but doesnt state if this holds true between carbed and efi versions.
Thanks
Last edited by Speedballalice; Jun 25, 2025 at 10:03 PM.
Advanced
Joined: Sep 2020
Posts: 64
Likes: 69
From: Denmark (Scandinavia, Europe)
Article about early vs. later heads: http://www.bigboyzcycles.com/showthread.php?t=91
I can recommend Hammer Performance. Did a late set of mine some years back.
I can recommend Hammer Performance. Did a late set of mine some years back.
Thread Starter
|
Intermediate
Joined: Oct 2024
Posts: 32
Likes: 29
From: Missouri
I appreciate the replies guys.
I guess what I should be asking in the simplest of terms as I tend to over complicate my questions....
Will the later intake flanges off of a later 07ish FI manifold fit on an earlier 04ish carbureted manifold?
Maxheadflow i believe you answered my question.
My apologies if someone adressed this and i missed it. Didnt see it on that website either.
I am excited about getting these sent off to Hammer. My buddy had them do the bore job in his bike and he is very happy. Although he went went with the SE heads.
I plan on getting the 98 cylinder bore and the Impact head porting on the 07 cylinder and heads i got and put them on my 04 heritage with an Andrews 37 cam and new tensioners. Hoping this will yield me 90+hp/tq with my factory CV carb. We will see.
I guess what I should be asking in the simplest of terms as I tend to over complicate my questions....
Will the later intake flanges off of a later 07ish FI manifold fit on an earlier 04ish carbureted manifold?
Maxheadflow i believe you answered my question.
My apologies if someone adressed this and i missed it. Didnt see it on that website either.
I am excited about getting these sent off to Hammer. My buddy had them do the bore job in his bike and he is very happy. Although he went went with the SE heads.
I plan on getting the 98 cylinder bore and the Impact head porting on the 07 cylinder and heads i got and put them on my 04 heritage with an Andrews 37 cam and new tensioners. Hoping this will yield me 90+hp/tq with my factory CV carb. We will see.
Last edited by Speedballalice; Jun 26, 2025 at 02:12 PM.
Advanced
Joined: Sep 2020
Posts: 64
Likes: 69
From: Denmark (Scandinavia, Europe)
You need the right flanges:
https://www.hdforums.com/forum/twin-...ttle-body.html
https://www.hdforums.com/forum/twin-...ttle-body.html
Last edited by lonbak; Jun 27, 2025 at 10:27 AM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,064
Likes: 7,591
From: Poolville
If you have the later 06 up heads why are you going with the TW 37.
The Woods TW-6-H at 10.5;1 comp would be a very good all around cam.. There are other cams as well out there that will perform very well at 10.5:1 comp..
You can easily produce 110 tq and 100 hp. Why settle for less when your doing a big bore with cams?
I don't think it's going to cost you any more that what your currently thinking of doing.
The Woods TW-6-H at 10.5;1 comp would be a very good all around cam.. There are other cams as well out there that will perform very well at 10.5:1 comp..
You can easily produce 110 tq and 100 hp. Why settle for less when your doing a big bore with cams?
I don't think it's going to cost you any more that what your currently thinking of doing.
Thread Starter
|
Intermediate
Joined: Oct 2024
Posts: 32
Likes: 29
From: Missouri
To be honest I'm all over the place with what I'm going to do.
I originally decided on the andrews 37 because of all the good threads i found on this combo, i will admit they were all old threads before the available of newer updated options.
everything I read told me the 98ci with 37s would net me acceptable results. Keep in mind I'm back in the game after 20 years and all my past experience was with evo engines, hence the leaning towards andrews...familiarity.
I'm kind of back to square one as some fueling 543g gear drive cams with gears have become available at a decent price, although I need to find out my crank runout before i pull the trigger on those.
My situation is the factory 88 suits me "ok" for my riding style just wish it had a bit more for 2 up riding and more pulling power on highway.
A buddy of mine offered his 2007 take off cylinders and heads to me for a good price so I have those.
my original thought process was.
Big bore (hammer)
Head porting (hammer)
Andrews tw37 cams
new cyco pads
But the greared cams give the opportunity to eliminate tensioners all together and the guy offering the cams says with what I want I would benefit from head porting.
It's a rabbit hole and the more I read and talk with people the more undecided i am.
Ugh
I would just like a solid 90/90+ bike with comparable low end to what I have now (or better) and an increase in mid/upper range for highway.
2004 Heritage
88ci stock with stage one
True dual fishtails
I originally decided on the andrews 37 because of all the good threads i found on this combo, i will admit they were all old threads before the available of newer updated options.
everything I read told me the 98ci with 37s would net me acceptable results. Keep in mind I'm back in the game after 20 years and all my past experience was with evo engines, hence the leaning towards andrews...familiarity.
I'm kind of back to square one as some fueling 543g gear drive cams with gears have become available at a decent price, although I need to find out my crank runout before i pull the trigger on those.
My situation is the factory 88 suits me "ok" for my riding style just wish it had a bit more for 2 up riding and more pulling power on highway.
A buddy of mine offered his 2007 take off cylinders and heads to me for a good price so I have those.
my original thought process was.
Big bore (hammer)
Head porting (hammer)
Andrews tw37 cams
new cyco pads
But the greared cams give the opportunity to eliminate tensioners all together and the guy offering the cams says with what I want I would benefit from head porting.
It's a rabbit hole and the more I read and talk with people the more undecided i am.
Ugh
I would just like a solid 90/90+ bike with comparable low end to what I have now (or better) and an increase in mid/upper range for highway.
2004 Heritage
88ci stock with stage one
True dual fishtails
Last edited by Speedballalice; Jul 27, 2025 at 03:19 PM.
Trending Topics
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,064
Likes: 7,591
From: Poolville
I get it, and I know what you mean about the rabbit hole It happens a lot. Hammer does do a damn good job and that 37 cam will definitely get you what you want if not a little bit more Just need to make sure you're static compression will be right around 10.1: 1.. They're very good at what they do...
Might want to consider manual compression releases and those cylinder heads it'll save a lot of life on your starter.. I personally believe any motor running 9.4, 9.5:1corrected should have compression releases..
Might want to consider manual compression releases and those cylinder heads it'll save a lot of life on your starter.. I personally believe any motor running 9.4, 9.5:1corrected should have compression releases..
Last edited by 98hotrodfatboy; Jul 27, 2025 at 04:09 PM.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
Thread Starter
|
Intermediate
Joined: Oct 2024
Posts: 32
Likes: 29
From: Missouri
I get what you are saying by getting more for not much more money if any.
Thought if I kept my cr just below 10 (many recommended around 9.8 with the 37 cams) I could forego the compression releases and the need for clutch upgrade. Im not looking for a hotrod....but...the more i look into things the more i wonder if im.just wasting money already not going for a higher hp/tq combo.
Now im thinking the the headwork is a waste and i could spend the money on the SE hyd cam plate conversion.
too much information....there wasn't so many options back in the day with the evos. Maybe I should have bought one..ha
Thought if I kept my cr just below 10 (many recommended around 9.8 with the 37 cams) I could forego the compression releases and the need for clutch upgrade. Im not looking for a hotrod....but...the more i look into things the more i wonder if im.just wasting money already not going for a higher hp/tq combo.
Now im thinking the the headwork is a waste and i could spend the money on the SE hyd cam plate conversion.
too much information....there wasn't so many options back in the day with the evos. Maybe I should have bought one..ha
Last edited by Speedballalice; Jul 27, 2025 at 05:44 PM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,064
Likes: 7,591
From: Poolville
The little bit more compression is free because you're buying pistons and boring the cylinders too fit..
The compression releases are relatively cheap $150.
As for the clutch I don't know what kind of upgrade you're thinking but that ain't going to be much more than $300 either.. For that upgrade all you need is the SE spring along with the energy one extra plate clutch pack.. They will easily handle up to 120 horsepower without the major expense..
I was actually going to suggest the SE conversion camp plate to hydraulic which will open up the door to many more different cam selections.. That ain't that cheap though to do the conversion..
There's nothing wrong with What you have.. Is it better? Yes, but absolutely not necessary..
Can you wrench? Cuz you can save a good amount of coin there as well.. there are plenty of people on here that can help you out and are you going with new lifters and adjustable pushrods?
Another guy you might want to check out is WFO Larry's machine shop.. He's pretty reasonable and might not hurt to give him a call and tell him what you're doing or should I say email and because he doesn't really answer the phone he does everything by email but his work is very good and very reasonable..
www.larrysmotorcyclemachine.com
The compression releases are relatively cheap $150.
As for the clutch I don't know what kind of upgrade you're thinking but that ain't going to be much more than $300 either.. For that upgrade all you need is the SE spring along with the energy one extra plate clutch pack.. They will easily handle up to 120 horsepower without the major expense..
I was actually going to suggest the SE conversion camp plate to hydraulic which will open up the door to many more different cam selections.. That ain't that cheap though to do the conversion..
There's nothing wrong with What you have.. Is it better? Yes, but absolutely not necessary..
Can you wrench? Cuz you can save a good amount of coin there as well.. there are plenty of people on here that can help you out and are you going with new lifters and adjustable pushrods?
Another guy you might want to check out is WFO Larry's machine shop.. He's pretty reasonable and might not hurt to give him a call and tell him what you're doing or should I say email and because he doesn't really answer the phone he does everything by email but his work is very good and very reasonable..
www.larrysmotorcyclemachine.com