It’s All In The Maths

Something a little different for you this week; we have asked our engine rebuilder to give us a taster write up of the technicalities of his work. Obviously we will leave out some of the trade secrets, measurements and settings, but this will give you an idea of what is actually involved in the engine rebuild process and why it costs what it does.

Take it away Dave, the blog is yours;

We were recently speaking to a valued customer regarding his very sorry sounding engine. It was agreed re-building his unit seemed the best solution and he asked if during the rebuild we could achieve more power. This is no problem, but the whole engine project needs to be planned from start to finish. Simply buying go faster parts and bolting them on can lead to a severe mismatch of parts and a disappointing end result.

The extra power was to be gained via some very nice alloy AFR cylinder heads and an up rated camshaft, then we have to consider modifying a lot of the remaining engine components to compliment these new parts.

For instance the AFR heads we used came with larger inlet valves which are great for airflow, but would almost certainly have hit the standard pistons. The piston valve clearance cut outs are machined to clear the standard diameter valves and a standard camshaft. With the extra lift from the performance cam, sufficient cut out depth needs to be considered.

The completely bare block casting was re-bored and chemically cleaned so new pistons could be fitted along with a new crank and camshaft bearings.

The engine is then dummy built to measure many clearances – especially the piston to valve clearances, it was evident the piston cut outs needed machining to clear the valves, also piston crowns were machined to desired height spec and then balanced as a set.

The AFR heads as lovely as they look were completely stripped down and all valves were checked for proper seal, also valve springs were checked for coil bind at full valve lift as without enough coil clearance they will break or damage camshaft etc,

The combustion chamber volume was checked and heads machined for desired compression.

The engine is then finally assembled with all new seals, core plugs etc , the rods are matched in weight as a set and ARP rod bolts fitted, new oil pump and performance pump drive, new timing chain set and front engine damper and camshaft timed as required.

Finally an often overlooked detail is the rocker arm contact point on the valve tip, if the roller doesn’t operate centrally on the valve tip the valves and valve guides can suffer. We used roller rockers to suit the AFR heads and after applying engineers marking blue, the engine is turned over to watch tip contact point – different pushrod lengths affect the position of the contact point and via an adjustable length pushrod a suitable pushrod length was chosen.

Then after the engine is fitted to vehicle it’s down to ensuring all the ancillaries are working correctly to cool and feed the motor harmoniously – then a lot of steady miles to bed everything in.

All this work and calculation is still only for a modified road engine, but must be done to ensure all parts work harmoniously together.

Thanks to Dave for taking time out and writing that up for us. If you want to know the cost, “then you can’t afford it”, as Adam would say. This type of engineering is an old school precision art form and not many can do it properly and that all comes at a price.

As ready built crate engines are becoming harder to get in the UK, this engine rebuild process is the only option. On the other hand, going down this route you know exactly what you are getting and the power you want is only determined by how deep your pockets are.


We have had a number of emails regarding the prototype seat extenders we featured a while back. We are satisfied with the results and we now have them in stock to buy here.

The prototypes were fitted by Mart D and this is what he had to say about them; “They are one of the best upgrades I have fitted to my car, they made such a difference.”

We have already shipped two pairs to customers who have been waiting patiently waiting for them. We wanted to make sure they were good to go after a season of car shows.

Christmas Gifts

We have waited until December before we mentioned Christmas. We sell lots of accessories for the petrol head in your life. Everything from little stocking fillers to full engines, gearboxes, axles, wheels, shocks etc. (Although we would like to see Santa bring a nice new shiny C4 transmission down a chimney!)

If you don’t know what to buy, give them the choice with our Gift Vouchers. You can buy them online and print them from home, no waiting for Royal Fail to deliver them (when they aren’t on strike that is). Click on the images below to take you to the WebShop.

Something we sold a number of last year was service kits, oil, oil filter, spark plugs, air filter, all tailor made for the particular model of vehicle. Drop us an email if you would like something similar or maybe a “petrol head hamper”, what would you want to see in it? Help us to help you.

Stay Safe & Take Care!

About Mustang Maniac

A business dedicated to restoration of Classic Mustangs. We supply parts for all ages of Mustangs 1964 to present day, servicing, restoration and custom builds. Anything your Mustang needs, we can help.
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7 Responses to It’s All In The Maths

  1. Gary W says:

    Fantastic blog as always. The team at Mustang Maniac and the small group of precision engineers that are part of the wider ‘family’ are a real credit to the mustang restoration and preservation industry. These skills are very rare and much valued in this throw away world. Well done Adam, Al and a special mention for Dave!

    Liked by 1 person

  2. Wow, I never knew it goes to that level taking apart new parts then reassembling again.
    Awesome work. Thanks for sharing.
    As for the hampers, generic kits for 289/302 oil and filter, then big block kits?. Winter kit anti freeze and screen wash?


  3. Hi, so much attention to detail indeed. The more performance, the more accurate it has to be. Thanks for the comments. We are looking at various options for hampers and your comments are what we were thinking.


  4. Simon says:

    Dear Mustang Criminals that has to be the BEST blog ever so you are all well out of a job now cos we wanna see more engine build please hahahahahahaha. GREAT pics too!!! Simon

    Liked by 1 person

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