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Herald Engine Numbers, manifolds and cam shafts

Eric Smith

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Hi Guys

I am here to talk to the Gurus of WIKISTANUMPH 

You were great and able to offer a lot of information last month when I was attempting to get information about the Herald engine fitted in my Standard 8

The engine number of the unit fitted in my car is GA180841HE

We know the engine is from a Herald (GA), 1147cc and is a High Compression Engine (HE).

We have spent ages on line and found bits of information but we could not find out the age of the engine and there was talk somewhere about a different (hot) cam shaft fitted to some cars therefore we would like to nail down a few things before we go any further - so can you offer help (we have mechanical knowledge) but please assume we are a bit dim.

My mechanic friend has asked me to find out the following:

1. If possible- Year of manufacture 

2. Which Spitfire or Herald Mark/Engines are closest to the engine we have fitted

3. Which Cam Shaft is (probably) fitted to the engine based on the engine number

4. Which of the Spitfire or Herald exhaust/inlet manifolds are compatible with my engine

5. Are there any other compatible manifolds from later Models

Many thanks guys - look forward to hear from you.


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The engine is a mid-range 1147cc; they were uprated a few times over production but the big update came at GA206641 in 1965, so yours is earlier. Early Spitfire 1147cc engines are the closest match, but almost any of their components can be fitted to upgrade the Herald engine.

I think - will bow to superior knowledge on camshafts readily! - that any of the small-journal camshafts will fit, Spitfire MK1 or MK2; I'm not sure about the small-journal MK3 as I think they're the same as the MK2? The Mk1 is 18/58/58/18 and the MK2 is 25/65/65/25. I think the 12/50 Herald received the MK2 camshaft?


The head is a six-port head, so any of the similar six-port 1147cc Spitfire manifolds or different 1147 Herald manifolds, such as the twin-carb version or units by Alexander, SAH or Mangoletsi, will fit, using twin SUs or twin Stromberg CD125s. You can split the Herald cast iron manifold into two parts, leaving the original exhaust setup but removing the inlet part to allow for different inlet manifolds. This cannot be undone, though! Later eight-port versions will not fit.

After trying to remember bits and pieces, and apologies for any inaccuracies, I found I'd already made a post a while ago:


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Spitfire cam info here http://auskellian.com/paul/links_files/spitfire_cam_specs.htm (if anyone knows of a similar resource that covers Heralds I’d be all ears!)

The Spit Mk3 has the same timing as the Mk2 but higher lift, and the cam bearing sizes I think are all the same up till the point where the large crank journals were fitted to the 1300 engine in the early 70s.

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spit mk2 and 3 cams are the same, they have the same part number though some sources say that mk3 has higher lift, they will fit the herald engine, though it will run direct in the block rather than running in cam bearings. I have a factory recon mk2 spec block which is actually a herald block so no cam bearings (that block is not used just acquired for spares). I think when they decided to not use cam bearings in about 1972 it was more cost effective to use a bigger journal cam as they had got rid of the tooling for boring for the small diameter non bearing blocks. Couple the mk2-3 cam with twin 1.25 SUs and a 4-2-1 manifold will give you the 67 HP of the mk2 spit. The only other major difference is the valves of the spit use collets rather than the fig 8 attachment plate and of course the spiral rear oil seal of the early cars and the diameter of the cam followers. Just be aware that the mk2 spit engine is very rev happy, which is fab in a sports car

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