What Am I getting into now?

[Ian Anderson]

Well that will teach me to play on the computer over the weekend

I just "won" a Ford 302 1971 block +20thou.

I'll collect it this weekend - and I suppose a FORD GT40 replica should have a FORD motor not a Morgan / Rover unit!

So now going down the route of building up a motor from it what do people suggest? Standard, stroker, internal balance, external balance 28oz, 50oz, what heads, pistons intake etc

At least this one will mean I don't have to worry about emissions!

Car will predominantly be used on the road with a bit of track time so I'm looking for some good manners in the up to 2000 rpm range which is where it lives in and around town.

Perhaps even manage to keep it to a single wire feeding power to distributor and go away with all the electrickery efi stuff! Perhaps even run mechanical fuel pump!

And I'd like to keep the expenses as reasonable as possible! (does that ever happen on a GT40?)

 

[Howard Jones]

Pump gas, 9.5 to 1, Hyd roller cam @ about .52 lift and about 280 duration, best alum heads you can afford, RPM performer intake with a 650-750 DP. That should get you about 300Hp/5500rpms at the wheels with good driveability. Plenty for a streetcar that sees a few track days a year.

You will be in a HP range for a nice R21. Use any extra money for a limmited slip. My advice.......Quaife TBD.

 

[Doc Watson]

Welcome to my world, I have a 1971 302 10 thou over bore block.

A 289 internal balance needs loads of mallory and im thinking of going up to 331 stroke internal balance and solid roller lifters as I want it to go up to 7000rpm and 10:1 comp. A dizzy with a petronix electronics system can be got for much less than a ECU unit and will still look the part. I just managed to 'win' a 1964 autolite dizzy (with period oil wick on the side for $10....yes $10 and its riding across the pond to me as we speak) and Im now thinking about heads (aluminium for sure) and cam profiles. My pistons will probably be custom as 10 thou over is not common but that was all that was required to get the bores 'true' and will allow for a 30 thou rebore to lenghten engine life. I also have period 48IDA's and no money left in the kitty.

Is it a mexican block? If you can find a supplier of a 289 internal balance let me know please.

Andy

 

[gtpete]

Hi Ian. Cubes are king !!! A 347 stroker kit is a good way forward. Companys like Real Steel do real good deals on kits. You can buy from the states but the weight of the parts !!! Aftermarket alloy heads are all good news, weight and performance wise. Lumpy cam and your on your way. Pete

 

[Jim Craik]

Guys,

I do not want to flaunt my ignorance, but then again, why not! What is this "internal balance" you speak of?

I have a 302 based 342R, does it have "internal balance"?

Thanks Jim

 

[Doc Watson]

A standard ford 302 crank dosent have enough metal on the counterweights to balance it and it requires extra balance known as 'external' balance. It also depends on the year the crank was made.

68-80 the 302 used the 28 oz imbalance
81 and later uses the 50 oz imbalance

 

[Jim Craik]

Thanks Doc

 

[Jim Rosenthal]

The block doesn't dictate the balance requirements, the rotating assembly does, BUT you have to buy a rotating assembly which will fit in that block. I have a 68 302 block- mine has the Mexico main caps but I don't know if I have a Mexico block. If you do, lucky you- they had a higher nickel content in the block iron and are stronger- some of the strongest 2-bolt SBF blocks.

I'd look to SCAT for a forged rotating assembly; look through their web site and their catalog. And years ago when I was researching heads, I found AFRs consistently had the best performance in shootouts and dyno tests. Have fun, you get to buy a lot of cool stuff.

Early SBF engines are 28oz, later are 50. It just all has to fit in the block AND all work together- crank, flywheel, harmonic balancer etc. Also the rear main seal has to be the right one for the block and crankshaft.

 

[Mike Pass]

Go for the internal balance as it will run much sweeter and is less likely to give the main bearings a a hard time at high rpm.. You will need a neutral balance steel flwheel and a neutral balance damper to suit. Most of the steel stroker kits will balance up without using heavy metal but by removing weight from the crank webs. 347 ci for torque or 331 ci for a bit freer revving. Any of the aftermarket ally heads will give a huge increase in output over standard. Edelbrock ( Performer RPM are cheap and good - AFR are probably the best but a bit pricey. The Trick Flow twisted wedge heads need different piston cutouts to the rest. A pair of ally heads will save 44 lbs of weight over iron - and high up too. Forged pistons are a must if you are going to "use " it. H section rods are a bit stronger than I section but a bit heavier. A standard pressure pump will do as an HP one can put strain on the oil pump drive shaft ( which should be a tough one as the standard ones are weak). The Edelbrock Performer RPM airgap inlet manifold gives 15-20 bhp better power than the normal RPM .
A Holley 650cfm double pumper will perform well and give reasonable mpg. Unless you want the look (and hassle and expense of quad webers). Don't go mad on the cam as it will be annoying in traffic. A road cam will give good low down torque and apart from an out and out track session will outperform a lumpy cam in most cases. I know two people who have taken out peaky cams and put in road cams with great benefit to driveability and all round performance.
Have your block checked for cracks and trueness. get new cam bearings, core plugs and get the oil gallery plugs changed to screw in ones. Clean all the oilways and the block until totally clean. Hot tanking will get most of the crud off it.
347ci with Edelbrock RPM heads and inlet and a road cam, 650cfm Holley will give about 420 Hp and 430ftlbs totque with 380 ftlbs at 3,000 rpm. Use a good gated sump to keep the motor fed with oil under accel, braking and cornering forces. get one of the distributors which have a low profile as most 40s don't have much room in that area.
Strangely enough I am doing one for my car at the moment!
Cheers
Mike

 

[Cliff Beer]

331 stroker, external balance, trick flow heads, roller rockers, sport cam, 44 IDF webers. Should be good for 400hp/tq at the flywheel (which is plenty). That's a nice engine for a GT40.

 

[Jim Rosenthal]

Can't emphasize the mild cam enough... I took a ridiculous bracket racing cam out of my Cobra's engine (no power below 2500, useless for street) that had been put in by the engine builder, and put in a Comp Hi-Energy; a much less impressive cam on paper, but gives the engine lots of low end grunt, smooth power curve, revs like crazy right to 6K, makes the car fun to drive like it wasn't before. Mild? yes. Fun- tons. Much better than the old impressive cam. Oh, and it idles pretty well too.

 

[Ian Clark]

I agree with the mild cam, more cubes, high flow heads. I struggle with stroke/con rod/piston deck height lengths/ratios as there's a case for every configuration.

External imbalance or zero internal balance hasn't been a concern, since the few and short occassions these engines see 6000 rpm in a light car with low aero drag, it probably doesn't matter.

Not to say I would miss the opportunity to build a sweet, free revving engine. I'd use every trick in the book.

However, crankshaft dampening is one of those black art sciences. A while ago I read a comparison test to see what happened when you went to a lighter dampener. This was on a internally balanced mill btw. Reducing the rotating mass in theory will reduce the hp required to wind up the mill, good thing. Where it gets tricky is that the hp loss due to crank harmonics will more than eat up the gains from a lighter dampener.

Also I wouldn't go as far to say there is any reduction in rotating mass with an internally balanced crank vs external balanced crank. Sure you don't have the 28 or 50 oz weights to spin but they were on a lighter crank to begin with. Just thinking out loud, gives you something to ponder

Cheers

 

[Ian Anderson]

Thanks guys - lots to think about - along with new belhousing, starter, exhaust, fuel system (I'm currently Efi)
I do know I want an engine that will be good on the road at low speeds - the current Morgan / Rover lump is great above 2200 but below that I'm riding a bucking bronco!

Ian

 

[Ian Anderson]

I collected the block and took it down to see Frank Catt - He had a look over it and confirmed it was in very good condition and could not see any of the normal cracks in the normal areas.

Now I still have not bitten the bullet and bought rotating assembly as I am not sure what size to go for - although a 302 (steel) crank to allow revs (Missed gears etc) sounds like the way forward to me as opposed to a 347 stroker (2nd choice)

Then because of this thread I have now been offered a Cleveland complete motor (At reasonable price) - only 35000 miles on it from new - from same era (I believe 1973 so emissions checks on it will still be "easy")
Owner says it's an "M" block which makes it a High compression motor.

Now
1) Were Clevelands ever fitted in GT40's - I believe not but did find a mention of 351 inch motor in a Mirage (not sure if cleveland though)
2) Does anyone know the weight penalty for going Cleveland over Windsor? - Presuming both on either steel or both on Ali heads?
3) Does anyone know if bellhousing mounts are the same for both ford motors? - If not the same I'll then need to find an adaptor plate.

MAny thanks in advance for any information

Ian

 

[Brett James-McCall]

I thought getting aftermarket Clevor stuff was not that easy. There is a lot of stuff inc adaptor plates for the Windsor.

I would still go for a 347, if it were me and make a nice torqey motor that would make a great road car. Once mine is on the road, I plan to upgrade the engine and box over a few years, hopefully to a 347 and a G50 or something that is stronger then my Audi.

Brett

 

[Mike Huddart]

Ian,
regarding the 351 Cleveland, the first question should be WHY !
Secondly if it is a Cleveland 351 M, the M stands for Modified and they were essentially smog motors produced into the late '70s They also did a 400. The worst feature for you is the bellhousing bolt pattern, instead of the normal 289, 302, 351W and C pattern they used the same bellhousing as the 460, very strange !
Out of interest the 351C and 351W are about the same weight, both are arround 65lbs heavier than a 302 in long block form.

If you are really, really bent on a 351C we have three proper ones you could have really cheap.

Mike

 

[Mike Pass]

Clevelands are boat anchors and aftermarket parts are harder to get than for Windsors so why bother. Go for the 347 ci Windsor (302 based) option with ally heads. There is no replacement for displacement! Ally heads save 47lbs over iron and modern aftermarket heads will be way better than old iron heads unless expensive serious porting is done so why bother? Less weight in the right place has to be the way to go for balance and handling.
An internal balance on a steel stroker kit is fairly easy to do and is a better engineering job than external balance. External balance was a cheap way of making engines back then. No need for such compromises now good steel stroker kits are easily obtainable. The steel flywheels and crank dampers cost no more for internal balance and are readily available. Buy a good quality crank damper (you get what you pay for) and the motor will be super smooth and will be durable.
Cheers
Mike

 

[John Fitzpatrick]

Ian-
Here's a thread with some info that might be helpful. http://www.gt40s.com/forum/gt40-tec...rack-boss-manifold-302-w-351-c-2-v-heads.html

 

[Rick]

Dont throw stones. Stock 289, Tuftride the crank for increased surface hardness. Good rods, Boss 302's do nicely. 10:1 Compression or slightly more (10.5) Solid Flat tappet cam with 232/242 @ .050. Rpm to 7000 if needed, plenty of torque, add IDA's and look out: 15% increase in torque. This will get you in all sorts of trouble. Lower piston speed, long life and easy on the block. 20 years on same Mexican 302 short block. Bullit proof
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