289 Re-build W/ Gt40 Heads - Need Suggestions

ks65stang · Jul 12, 2012

Finally got around to rebuilding the engine. Would like the engine to put out 275-300HP on 87 octane pump gas w/ milage in the low 20's......if possible. More concerned w/ OK-good milage for long trips and stop light to stop light performance. I'm looking to build a daily driver / street car. Transmission is a 5.0 T5 w/ 3:50 rear end gear.

Block is at the machine shop now and is getting cleaned and bored .030 over. Parts I have are 66 289 block, stock crank & rods, rebuild GT40 heads (been decked, guessing 63CC chambers), Edelbrock Performer 289 manifold, Edelbrock 600 CFM carb. Hooker headers w/ 2.25" dual exhaust.

I bought the heads professional rebuilt for $375 which was less than $500-700 quoted to rebuild my stock 289 heads. I know I will loose some compression and I'm a little worried about that....

Should I be concerned about the compression loss? I would like to buy .030 stock pistons to keep the cost low? If not what super budget friendly piston would be best to increase /retain the compression? What to re-use the stock rods and crank.

What cam? I don't what something super loppy that it sounds like a full blown race car. I was thinking the Edelbrock Preformer camshaft?

Also what rockers? I'm leaning towards the Ford Sportsman 1.6 from Speedway?

Budget I would like to try to stay in:
Master Engine Rebuild (stock pistons) $270, Not purchased yet
Harmonic Balance $80, Not purchased yet and mine needs replaced
Cam & Lifters $130, Not purchased yet
Heads GT40 $375 Purchased
Rockers Studs $100.00 Not purchased yet.
Machine Work $300

I had all the other stuff. Thanks in advance!!!

robbz28 · Jul 12, 2012

If you rebuild the bottom end back to stock specifications (maybe a little taller piston to keep the comp ratio around 9.5:1...your machine shop can help you there). Take those re-worked heads and do a light port / polish job on them. I would say a 270 ish cam with .490-500 lift (if you are using hydraulic flat tappett). The intake, carb, and other items you have should work with all of that. All the horsepower in an engine is made in the heads and how well they flow. I don't think you would be at 275 just bolting together what you listed there, maybe 250. If you have a little extra money that you can throw down on some new higher flowing aluminum heads that will make a big difference (but not TOO big of a runner, that makes you lose velocity). Another thing is that tranny and rear end...depending on your final ratio of your T5 you would probably want to use 3.73 rear gears. Lower RPM's don't necessarily mean higher MPG, your engine will have a "happy place" also depending on what speeds you intend to cruise at. All this I discussed is the tip of the iceberg...I will let the other guys fill in what I missed...good luck!

ks65stang · Jul 12, 2012

The 3:50 gear and heads have to stay, no changing these items. I'm ok w/ 250HP+. My buddy has a stock 95 5.0 Cobra and I think its power is comparable to what I want.

woodsnake · Jul 12, 2012

I like this engine kit:
http://www.summitracing.com/parts/FEM-MHP172-311/
Something like this, for a cam kit. Notice that it has the springs, timing gear, retainers, etc that you would have to replace anyway.
http://www.summitracing.com/parts/CCA-K31-218-2/
Just about any body's roller rockers are good any more, I like harland sharp, but they are kind of expensive:
http://www.summitracing.com/search/...ine-Size/4-7L-289/?keyword=ford+roller+rocker
You are going to need hardened pushrods, with the adjustable valve train. (guid plates)
You can get a lot of deals on used hard parts like roller rockers, corral dot net has a VERY active used parts board.
Craigslist also is a good place to get stuff used.

ks65stang · Jul 12, 2012

My machine shop suggested I install flat top pistons to make up the compression. My current pistons have a 1/8" deep half dollar size dish to then w/ valve reliefs. Makes sense to me.

I was considering a camshaft with 204/214 degrees & .448/.472 lift / exh. Is this too little of a cam?

rbohm · Jul 12, 2012

ks65stang said:
My machine shop suggested I install flat top pistons to make up the compression. My current pistons have a 1/8" deep half dollar size dish to then w/ valve reliefs. Makes sense to me.

I was considering a camshaft with 204/214 degrees & .448/.472 lift / exh. Is this too little of a cam?

that is a nice mild cam that will let the engine make about 250-275hp, perhaps a touch more given a proper tune. for a little more power i would go with the next step up cam that has about 10 degrees more duration, and .472/.496 lift. still a smooth idling cam, but about 40 more hp as well, and the fuel economy wont suffer.

2+2GT · Jul 13, 2012

The flat pistons are an excellent plan.

A guy near here used port-matched iron heads on his 67 289 (he did the matching himself, his first try), a 600 cfm carb, Edelbrock Performer RPM intake, stock distributor curved to BOSS 302 specs, and a C9OZ-6250-C cam, the Ford hydraulic version of the C3OZ-6260-C 289 High Performance cam. Engine was run-in on a dyno, and turned 323.5 hp @ 5300 rpm. Smooth idle, with daily-driver performance.

Oh- Your $100 for rocker studs is about twice what you should be paying, unless that includes installation.

As for pistons, hypereutectic should be more than enough. I used TRW forged pistons in my 289HP, but that's actually massive overkill. The factory piston in the 289HP was the same cast flat-top as the 289 4V.

PoppyMod · Jul 13, 2012

Hi,
I suggest, you have the shop do the math and calculate your compression ratio (C/R). You should shoot for a 9.5, or so. CR. It's easy enough to shave a couple of thousandths off the head, not to mention the various choices in head gasket compressed thickness.

ks65stang · Jul 13, 2012

Good feedback!!! The place I'm buying the master engine kit from wants to sell me what they call their 272 cam. (272/272 lift .475/.475). I think after your comments I'm leaning this way.

I meant $100 for Speedways ford Sportsman Rockers & studs.

Thanks!!!

Fstbk · Jul 13, 2012

I would run higher compression pistons for certain.

Also, I have not seen anyone mention cam overlap. that can also change how your engine runs with lower compression. If you are not going to use taller pistons to get your compression back you definitely need to consider the overlap.

woodsnake · Jul 14, 2012

Keep in mind, that with the new cam, your power band will also affect, and your overall performance will be affected by, your final drive ratio.
Look at the cam cards to determine final drive gear requirements as well as torque converter requirements. A nice choppy cam, will require at least a 3.50 rear end gear. If you have a 2.79 ratio right now, you may want to add that into your engine build planning.
It all needs to work together, torque converter, power band/camshaft, gear ratio.
Otherwise, you will not realize the gains that you are investing in...
(edit for grammar and spelling!)

bartl · Jul 14, 2012

IMHO, you aren't going to be running 87 octane in an iron headed, carbureted - non electronic controlled SBF with anything over 8.5:1 compression without giving something up in the cylinder pressure department (hence camshaft profile to keep preignition at bay). You may be able to increase cylinder pressures by running a spark control unit to retard spark at certain rpm ranges to compensate.

289 Re-build W/ Gt40 Heads - Need Suggestions

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