GT40 Engine Build Mirage Chassis

[dave harris]

Hey Doc,

I asked the same basic question of Gordon Levi - see below - and his response follows - I don't know how close to my engine spec's you are, and you must keep in mind that we are limited to what max octane ratings we have in "pump" gas for the street - - - anyway - his opinion matches with what I've experiences (especially with the type of cam I'm running & 10,5 to 1 compression and higher on our pump gas).

, can you suggest a spark plug and initial msd distributor timing set up for the following engine specs? And, thanks for your time, inputs and advice.

65 289 block & crank - fully prepped & rotating assembly balanced
custom long rods & lightweight pistons - ~ 10.5 to 1
comp cam - solid roller - 575 / 579 lift, 290/294 duration, 109 sep
victor junior heads
air gap rpm or victor jr intake (i have both, but the victor jr extra height may not fit in the gt 40)
holley 4150 hp pro 650 cfm carb
msd pro billet dist & 6al box
full crossover exhaust
\
Gordon's answer:
I'd run an autolite 3924 and gap them to .035.
That engine isn't going to need any more than 30-32 degrees of total timing, probably closer to 30.

[Peter D]

My 331 is running about 10:1 on 98 octane, with AFR 165 heads, Autronic ECU & 8-stack. The timing is set :

800 rpm - 10deg
1000 - 15deg
1500 - 20deg
2000 - 35deg
3000 up - 38deg

These figs are for up to about 80% load. Up at 100% load, we've got from 5deg @ 800, thru to 32deg at 5000.

Somewhere around these number should work fine - mine starts up with just the key, idles at 900, & runs sweet from there up.

Let me know if you want the full map.

Kind Regards,

Peter D.

[Doc Watson]

Thanks Guys

My engine is running 10.5:1 compression (sorry omitted that info).... so it looks like about 30 degrees max advance should be used, which means that I would need 4 degrees initial advance using the 13 degree centrifuge slot.

Its a standard 2 bolt 289 block, original iron heads and a 'mild' cam. Im looking for 300 HP which will be enough for me.....

What effect will the initial advance have on tickover, I want the engine to rev at about 800 at idle or is this more a function of the cam profile?

Regards Andy

[JimmyMac]

Andrew,
Is this a HiPo block with the heavier main caps for 300hp ?

[Doc Watson]

Its a 2 bolt 289 not a HiPo, on reflection 300 might be pushing it but its something to aim for. Spec is....

Engine Block Casting Code - C6AE-C

C=1960
6=1966
A=Galaxie
E=Engine
C=Design Change

6 bolt bellhousing, 2 bolt mains. Block stripped, hot tanked. Engine re-bored for first time to 4.030 inches. Original crankshaft inspected and bearing surfaces cleaned (ground). Eagle H-beam rods with ARP bolts for mains and rod bearings. Aluminium pistons. Original cover plate, hot tanked.

Heads Casting Code - C6OE-M

C=1960
6=1966
O=Fairlane/Torino
M=Design Change

54.5cc chamber. Intake valve diameter 1.67 inches, exhaust valve diameter 1.45 inches.
Heads stripped, hot tanked, phosphor bronze valve guide bushes inserted, stainless steel exhaust valve seats. Titanium valves. Roller followers. Inlet manifold with twin water inlet and correct Weber orientation (although from previous discussions with you James there in no 'correct' weber orientation). Set of 4 x 48 IDA Weber carburettors. Aviaid GT40 oil pan. Melling hi flow oil pump. Fram Filter and will eventually get a sandwich plate and remote oil cooler.

I havent got the cam details to hand but will hunt them down.

Do you think that 300hp is asking to much from the block?

Even an honest 250hp will be more than enough for me.

Andy

[JimmyMac]

Andrew,
There are those who will dispute the Weber orientation and prefer opposing Weber carbs as the manifold mixtures flow better ?
I now believe this since I will prefer to rely upon the views of the experienced rather than the casting salesmen these days.

Personally I would blueprint to the lower output as the original HiPo mods to the lower mains were made to maintain 271hp.
Depends on how you drive the engine and how long you want to keep it I suppose.

[Doc Watson]

I like aluminium......

[Doc Watson]

Oh... and billet steel has its place....

[Ron Earp]

Beautiful pieces you've assembled for your car/motor!! Intake and exhaust valves are sort of on the small side for 300hp, I think. Depends a lot of cam and head, it might take a pretty good cam to get the power of out it. I also suppose it depends on if you are shooting for 300 gross hp, aka 1960s ratings (K code, 271hp, A code, 225hp), or a modern SAE 300 hp. There is a good sized difference there.

However, your build and blueprinting is worth something and might make up some of the SAE/Gross numbers as well. I'd be interested to see what it comes out to on the dyno - no matter what I bet you'll be pleased and it'll be a fantastic drive!

Ron

[Doc Watson]

Hi Ron,

I'm aiming for a realistic 250 from the engine more pictures soon. I could get more from it I'm sure, but with only 2 bolt mains 250 is about the limit. I will look at a girdle for the bottom end if more is needed although could cause interferance problems with the aviad pan... soon find out when the short block arrives.

Also finalised details of the mono chassis last week and cant wait to get my hands on her......

Hows that austin healey?

Andy

[Keith Hardy]

Andrew I don't know whether this is relevant but I "ventilated" the Hi-Po block in my '67 Shelby and replaced it with a standard 289. I did all the usual stress relieving, deburring stuff and refitted the HiPo main caps (a little thicker & stronger) had it line bored and re-assembled. The motor was at 306hp spec and stood up to everything I threw at it. I do believe that that particular motor is still running today some 20 years later..

If it's blueprinted and balanced well, then I don't believe you'll have too many issues with the stock 289 block if you start with a good one...

Hope it helps....

[Ron Earp]

Hey Andy,

I don't think you need to worry about a 250 hp limit on a built two bolt block. If that were the case then literally 100s of 1000s of Mustangs running around in the US with everything from blowers, turbos, and nitrous are all way over the limit. In many cases 300 to 400+ rear wheel hp over. Occassionaly a stock build will be toasted, but there is usually a such as 20 lbs of boost, too much nitrous, etc. Every 5L Ford I've owned was a two bolt block without failures. The only time I've ever heard anything about a Ford 2 bolt main hp limit is from a Chevy builder, and you can't trust those guys!

As you say, if really worried fit a bottom end girdle. I've got one fitted to my 500hp motor. But the mild 300hp enduro race motor I have has no girdle and it'll be okay. You'll be perfectly fine at higher hp numbers so go ahead and build that thing up a bit!

Ron

[Doc Watson]

Got hold of two of these from a friend across the pond.....

[Doc Watson]

Moving on......

Hartwells and dash knobs..... and thats grease on the Hartwell latches and WD40 not rust.......I think I ordered to many ;-)

Engine was supposed to be delivered today but was delayed (AGAIN) so the coffee is on hold...... glacial progress.......

Andy

[Gary Kadrmas]

Doc,

The parts you are using for your SBF will work just fine. You will be surprised how well it will work. And as far as HP figures, who cares. A bone stock "A" 289 was 225HP (single four barrel). Adding headers, improvements (heads/porting) to the intake and exhaust flow rates alone, will jump the HP figures to around 275ish, and the cam should get you close to 300ish. So I think you are right on.

You mentioned California.......well, California is downunder Oregon, on the Pacific Coast....where Lewis & Clark spent the weekend that one time.

The coffee table......Damn, nice coffee table. I wish I had one. Specialty coffee tables are usually only found in garage sales......and I have been to my share of garage sales, and have never found a coffee table like yours. Consider yourself lucky. Nice job, and good luck on your build!!!!

[Doc Watson]

NOS CAV Ammeter

[Doc Watson]

Washer bottle, incorrect motor but I'm on the case....