Aluminum block?

hey guys...
thinking of going with an aluminum block in my SPF Mk2.
any downsides?
besides cost.
:)
thanks
 
Dart aluminum block here. If you can swing the extra $$$ there really is no downside. They can handle the power and save a decent amount of weight.

My .02
Rich.
 
Alloy in my RF. Some slight fitment issues as the block was not identical in dimension to a conventional block. Nothing too hard from memory.

Tim.
 
None really-BUT, I do think that you need to spend a bit more time checking stuff like intake/pan/front cover bolts etc on a regular basis along with cyl head bolt tension.
Most of these issues have been addressed now with good fastners etc, but I can remember when the first SVO cleveland heads arrived on the scene that the outboard head bolts would sink down into the cyl head due to the alloy expansion in this area.

Also try really hard not to get into an overheating situation-Alloy doesnt like being taken past a certain point temp wise and if the block/heads get real hot then all manner of 'little' issues start to come out at a later date. Dont let that put you off though, just dont give in to the 'I might get home if I drive real slow' bug!

Most have steel or iron main bearing caps and this can result in a small oil leak in the rear main area from sealant degradation over time due to different expansion rates etc.
 
Mike, are you thinking of an aluminum small block or big block?

My experience with all aluminum engines is that they tend to leak more due to greater thermal expansion than steel. Even if everything (heads and blocks etc.) are all the same alloy and heating and cooling at the same expansion rates, there's still more movement and walking around on the gaskets and seals so seals tend to wear out faster and leak more easily. Additionally, some alloy castings are so bad that the metal walls are actually porous and can leak right through - you find yourself looking for a cam cover leak or a rear main seal and then you realize the oil is coming right out the side of the block! This is rare, but nevertheless real.

I've been looking into an aluminum block SBF stroked to 347 as this doesn't present too many fitment problems - should save 50lbs over the steel block. What concerns me is what appears to be a lack of additional ribbing or structural reinforcement over the steel block - aluminum isn't as strong by volume and so I can't imagine how a block of the same casting dimensions could have equivalent longevity. Something to think about at least.
 
I've been looking into an aluminum block SBF stroked to 347 as this doesn't present too many fitment problems - should save 50lbs over the steel block.

Take a look at Joe Fontana -
Welcome to Fontana Automotive

We used a 302 Clevor - bored/stroked to 347 on Roy's Mk1 GTD - Very effective for a number of years till its demise following an overheating incident.

Cosi Sergiovani (Aus) has one too with twin turbos fitted in his Mk1 GTD40.
 

Randy V

Moderator-Admin
Staff member
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Lifetime Supporter
My last experience was with Dart Alloy blocks for Chevy applications - but here goes;

They would leak coolant at the cylinder sleeves unless you used a pint of Ceramic Sealer in the coolant to seal them up.

They had no way of using the factory (OEM) Oiling Systems and required external dry sump.

They were very strong and we had no block related issues that I'm aware of.

We were pushing 820-830 HP from 435 CID with a single 4 BBL carb.

edit - this was ~10 years ago. Things may have changed since then
 
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thanks for the replies...
i hope we dont have any heat/coolant related issues or mysterious leaks.
other than those concerns i believe shedding 100+ lbs from a light mid engined car will be pretty cool. anything you can do to shed weight from the back of a mid engined car is always good.
ill certainly post more as we move along.
 
I have a all alum. Dart block..Stroked 540 hp NO LEAKES no problems. If you use Alum. Heads, you will save 150LBS weight. I t was the best choice I ever made.

John
 

Sandy

Gulf GT40
Lifetime Supporter
Have both the SVO Aluminum SBF and Dart. The SVO has run for about 4 years in the mustang with no problems. Second one going in after over rev bent valve. The RCR GT40 has a Dart from Kieth Kraft, and I have another Dart for the Sunbeam Tiger. Nothing but good ;-) A few dimensions are different due to screw in freeze plugs so check motor mounts before putting it in. Also minor other things to watch out for like oil pans and the 4 bolt blocks are not a slam dunk. Rear cap needs shaving or pan need the bulge. Also on the Dart for the Tiger one of the center caps seems to be in the pan a bit too. That kind of stuff. Also make sure that you have the block done by someone who has done them before. The SVO needs TLC to get them going, like sleves final pressing, some minor oil galley clean up etc. The Dart might be a bit less. Head gasket is also important with the SVO, not sure about the Dart.

Sandy
 
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