Pull the piston, rods and crank from the 71 block and use them!

i was thinking that this is somewhat of an old direct connection bracket entry level or street performance engine. I was looking at a October '86 hot rod magazine 440 build up by Arrow. they got 406hp with the '631 cam, '452 heads (appear to be un-ported), 3310, holley SD, and headers. this is an 11:1 engine so 8:1 is going to knock that down to 350-360hp; better than a 10:1 magnum engine. I bet a set of kb184's to match the heads will add another 20hp. pocket port the heads and another 20hp. 380-400hp in a 3400lb car can get into the 12's rather simply.

446, kb184’s, std valve 346 heads with a very minor/quickie bowl blend(3hrs for the pair, tops), 6bbl, 1-7/8 headers, comp 280h cam.......499tq/424hp

The thing about working the heads is it's just your time, spend an hour per hole and do it nice. Make all the power you can.

One thing on the 452 head dont touch the floor of the intake or the radius to the valve. The 452 out flows the 906 and all the others to 5.50 lift.

I think what I dislike the most about the '452's is the screwy intake guide boss. why was that fat thing needed?

that would be a fun docile-easy driver street engine.

I just machine it down to .625 so it’s the same as the exhaust and earlier heads.

Indeed it was......... in a Cuda with a 4 speed and 3.55’s.

We're going to have to agree to disagree on those statements above. I know that Don Dulmage said the short turn on the 452s shouldn't be messed with, but they won't show their true potential w/o work there.

906s have better under-.500" #s than the other standard OEM iron heads. The short turn work they need is to keep the flow from dropping off at higher lifts.

There are still some good threads by Dwayne Porter on porting OEM BB heads stuck out on the "old" Tech archive linked from Moparts' home page, but you have to dig down a couple of levels to get to them.

That's what die grinders are for....

No touch short turn = no big flow.

Sure....... you need to know what you’re doing....... but you def need to rework the short turn.

HERE!!!

I bet a lot of more recent Moparts members don't even know about the "old" Tech Archives, either.

I've only had two of my motors with my iron heads on the dyno, one is the 9.5 452" with 452 heads and it made 520 hp and 545 ftlb torque, I was pleased with the numbers considering the compression ratio. The other is 500" 12.5 cr 915 heads that made 645 hp and 620 ftlb torque, I'm figuring that TF 240 heads would have gotten me 60 hp from the other builds I've seen on the same dyno.

i'm not referring to inside the port.

THere are no tricks being done here. It is so mundane that it probably is from about 1985. It is even getting fenderwell headers.



I do have a decent convertor and I should be getting a RMVB in the mail today I picked up etc. That and 3.73's.

My other a body was stock other than the SD intake and a RR cam and with 3.55's it was fun. This car should weigh 3-400 less with more gear, exhaust etc.

Still gathering pieces. Have an MSD question I will ask in general tech.

Oh, and regarding using the 71 pistons, the engine is a 76. I am using all the swap parts out of it and putting them in the other car.

that engine may not need a bunch of gear or converter. I use a stock 10 3/4" converter with a 3.23 gear with an engine with more cam than your using in a car that may be 500lbs heavier; without any issues. I think the tune-up is key.

Well the convertor is a PTC 9.5" that flashes to 4200. Guy put it in and then drove it, but converted whole car back to stock.

I got it for $175 I think. I am way more of a 3.55 guy, but the Explorers came with a variety of ratios, and the 3.73 is pretty common and that is what is in there.

If I were buying new, I would be aiming for more of a 3k convertor and lower 3's for gears.

I would imagine though that a convertor such as mine and the gear will only help in the quarter.

that converter is too loose. a proper ignition curve will work wonders. loose converters and low gears are just a crutch for other issues. they can waste energy.

My old '73 re-ring 440 combination (pretty much the same except 484 instead of 474) ran it's best ET with a 9" converter and 4000-ish stall.

Just trying to say personally I think it will be fine, no worries.

I can't tell you what hp you will achieve if you do or don't do some work to the heads, but I can say it would be a worthwhile test to run it both ways.

There has never been a more perfect application for P4286754 head gaskets. I hope you can use them.