Discussion
If future value bothers you yes but in all reality there wont be much difference on the road. The HC will rev a little better but the 450 will have more torque low down if thats your thing.
Its all about the health of the engine too ie camshaft wear as this makes a difference, they hide their problems quite well.
Its all about the health of the engine too ie camshaft wear as this makes a difference, they hide their problems quite well.
Parts availability is the same really on the 400 and 450. They basically had cam changes, exhaust work and remapping, very few got head work but back in the day it wasnt unusual to have fruitier heads fitted if thats what they had laying around and you got lucky.
Some good info here on the engines.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Some good info here on the engines.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
The 4.0HC is nothing more than a more radical cam and vernier timing gear set and nothing more 
certainly no head work or further mods, IMO a healthy 450 will blow a also healthy 4.0HC into the weeds performance wise , but like always buy on condition rather than spec 
however the 450/4.6 is a better model especially for further performance increases
certainly no head work or further mods, IMO a healthy 450 will blow a also healthy 4.0HC into the weeds performance wise , but like always buy on condition rather than spec however the 450/4.6 is a better model especially for further performance increases I had both and rebuilt both .
I had a 400 HC and rebuilt the engine fully then bought a 450 and rebuilt that and put it in the car .
I really think the difference is so marginal, you go hunting for a difference . I made ECU changes and fuelling yet the 450 was not noticeably stronger .
I had a 400 too also rebuilt and in truth the difference to the 450 did not seem huge .
Its such an old engine now that steps in performance are not linear with cc, in my view.
I had a 400 HC and rebuilt the engine fully then bought a 450 and rebuilt that and put it in the car .
I really think the difference is so marginal, you go hunting for a difference . I made ECU changes and fuelling yet the 450 was not noticeably stronger .
I had a 400 too also rebuilt and in truth the difference to the 450 did not seem huge .
Its such an old engine now that steps in performance are not linear with cc, in my view.
Ah, the old HC issue again 
.
Over the years there's been plenty of debate as to what a 'genuine' HC is, or was, from High Compression, High lift Cam, and it does/doesn't have further head work , to 'nothing at all'. The reality is as set out above, ie cam etc. but no additional head work over a 'std' 400.
I would buy purely on condition, with a preference for the 450, everything else being equal.
. Over the years there's been plenty of debate as to what a 'genuine' HC is, or was, from High Compression, High lift Cam, and it does/doesn't have further head work , to 'nothing at all'. The reality is as set out above, ie cam etc. but no additional head work over a 'std' 400.
I would buy purely on condition, with a preference for the 450, everything else being equal.
Belle427 said:
steviegtr said:
My 450 2001 has a cross bolted block. They say holds the bottom end more rigid. Not sure if the 400 has that.
Steve.
All 450s were crossbolted but 400s were not iirc.Steve.
I bought 400HC Chimaera new in 1995. TVR rather cheekily positioned it as a separate model between the 400 and the 500.
While in reality, as has already been stated, it was just a more radical cam and a different ECU chip.
It did run very sweetly and didn’t seem to trade off low end performance despite a peakier cam.
Today I’d probably opt for the 450, given the choice, but there’s nothing wrong with the 4.0HC.
Henry Cat said:
I had both and rebuilt both .
I had a 400 HC and rebuilt the engine fully then bought a 450 and rebuilt that and put it in the car .
I really think the difference is so marginal, you go hunting for a difference . I made ECU changes and fuelling yet the 450 was not noticeably stronger .
I had a 400 too also rebuilt and in truth the difference to the 450 did not seem huge .
Its such an old engine now that steps in performance are not linear with cc, in my view.
IMO like for like spec wise that extra 600cc is worth 25hp + and a similar hike in torque , i'd say thats noticeable alright , some of the last 400's had cross bolters rather than the interim serps fitted I had a 400 HC and rebuilt the engine fully then bought a 450 and rebuilt that and put it in the car .
I really think the difference is so marginal, you go hunting for a difference . I made ECU changes and fuelling yet the 450 was not noticeably stronger .
I had a 400 too also rebuilt and in truth the difference to the 450 did not seem huge .
Its such an old engine now that steps in performance are not linear with cc, in my view.
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