73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: chronos on December 11, 2009, 10:25:44 pm

Title: Advise on big block
Post by: chronos on December 11, 2009, 10:25:44 pm

Thinking of this engine and hoping for some input from some knowledgeable guys...
here are the details that I have been given:

454 complete carb to pan,manifolds,QJ carb, flex plate.1974/781 heads,68 hi rise intake.brackets,
2 bolt cast crank. 781 heads(these are very good oval port heads that i am often asked to find as replacements )
it is a 1974  289 block, 1968 cast hirise gm intake,with a QJ carb, car manifolds(if you want them)
stock camshaft, pulleys, alternator bracket ,no ps bracket ,water pump,flex plate for auto trans,accel ignition on distributor

Title: Re: Advise on big block
Post by: joesgarage71 on December 11, 2009, 10:31:13 pm

 :o Oh yea! don't expect to many liters per klick with that Horse

Title: Re: Advise on big block
Post by: chronos on December 11, 2009, 10:37:00 pm

Is that a yea or a nea.....lol

Title: Re: Advise on big block
Post by: VileZambonie on December 12, 2009, 07:29:16 am

Very easy power maker right there. Those are very workable heads and a strong casting block. Even the cast crank in there is stout. I'd go through it and build it for your intended use but if it's a good deal snag it.

Title: Re: Advise on big block
Post by: chronos on December 12, 2009, 08:02:43 am

Thanks , the guy wants $900 for it
He tells me that , beleive it or not, it was is a MUSTANG !!
and he pulled it to go with FORD BB
Seems like a good buy to me , should I go for it??

Title: Re: Advise on big block
Post by: malibu795 on December 12, 2009, 10:31:48 am

Quote from: chronos on December 12, 2009, 08:02:43 am

Thanks , the guy wants $900 for it
He tells me that , beleive it or not, it was is a MUSTANG !!
and he pulled it to go with FORD BB
Seems like a good buy to me , should I go for it??

grab it!!!!!!!!!!!!!!

781 and 049 are the to best O-port head factory made..

swap the camshaft for a after market one..  stock  dual pattern cam with .400 lift @ the exhaut and some 160-170* @ .050 lift..


i know several people ahve taken the stock crank to 700hp reliable.. rpm limited to about 6,000rpm.. some of the drit track guys push 1000hp on stock cranks... granted the car is 2200lb or so

stock compression was 7.5-8.25:1 from the factory.. a 10-12cc dome will put you close to 9:1
i picked up 15% airflow just removine casting flash on the 781 heads... and stock valve DIA... useign a superflow 600 flow bench.

Title: Re: Advise on big block
Post by: drag80 on December 12, 2009, 03:55:01 pm

 i have the same heads on a .030 over 454 with a mild hydrualic flat tappet cam and make 460+ hp and 525 ft lbs of torque
good deal

Title: Re: Advise on big block
Post by: Engineer on December 12, 2009, 08:36:26 pm

Sounds like a good deal.

I would freshen it up with new rings, and bearings while I had it out.

Of course adding a strong hydraulic lifter cam, and headers will give it more life as well.