What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

454 with 781????

C

codytr1

Registered Member
Joined
Oct 26, 2007
Posts
35
Reaction score
0
Location
Collinsville,oklahoma
I am buliding a 454 that was in a 87 1 ton. It has the stock bottom end.All of the fuel injction stuff is gone. I am going to run Xtreme Energy 268 cam,performer rpm intake, 2 in headers, holley truck avenger 770 carb.I got some 781 heads and I want to go with 2.19 and 1.88 valves. Some people have told me that I cant because when machining the seats they will hit water? I want to be some where around 9.0-10.0 comp with just head work and run pump gas. please help any input would help
 
codytr1 said:
I am buliding a 454 that was in a 87 1 ton. It has the stock bottom end.All of the fuel injction stuff is gone. I am going to run Xtreme Energy 268 cam,performer rpm intake, 2 in headers, holley truck avenger 770 carb.I got some 781 heads and I want to go with 2.19 and 1.88 valves. Some people have told me that I cant because when machining the seats they will hit water? I want to be some where around 9.0-10.0 comp with just head work and run pump gas. please help any input would help
Click to expand...

Pretty sure you can run them just fine... my 468 has some kind of 80'ish block, and 781 heads with big valves (the numbers sound right, but I never remember.) And yep, I can run on the low-octane stuff and get the same kind of hp/tq that GM gives you in their HO502 -- except it wants high-test! :deal:

Our resident (actual honest-to-gosh professional does it for a day job) engine machinist guy should chime in, but here's some threads about motors Scott has done that combo on, mine included:

http://coloradok5.com/forums/showthread.php?t=202575

http://coloradok5.com/forums/showthread.php?t=213735

-- A
 
codytr1 said:
What kinda of hp & torque am I looking at
Click to expand...

Well, I did a Qjet on an Edelbrock Performer (not the 2.0, which IIRC is aimed at higher RPM) and headers in addition to the motor proper, and Scott gave me numbers in the region of ~450hp and something nutty like 550+ ft-lbs. :eek1: :bow:

It's in my crewcab, which will never win any awards for handling -- or style -- but it can certainly get out of its own way! It's enough of a sleeper that I've shamed the occasional ricer, and out-did a Mustang the other week ... up to about 50 anyway :surepal: TH400's are great, but they don't have so many gears options :haha:

-- A
 
Thanx I am running a Sm465 & 4.56 with 35's not looking for speed just alot of torque to spin the tires with and make a whole lot noise. The neighbors just love me LOL:haha:
 
Wow, I plan on doing the same thing with the same parts in my 454...Hoping to lay some nice patches with the boggers.....
 
781s are basically carbon copys of the 049's I have on my 496. Im runnin 2.19/1.88's and a pretty good port job on em. No problems.
 
Yep, Aaron (Dremu) got it right. I built his engine and used the "781" heads and installed 2.19/1.88 valves and blended the bowls and put him close to 9:1 to keep the engine happy with low grade fuel and no detonation. You want to stay as close to 9:1 as possible especially in a heavy vehicle.
 
Yep 781 heads are a good casting head. They flow pretty good in stock form, just like and real similar to 049's as has already been mentioned. Ive ran 781's and 049's on a few different 454 motors and they always performed decent. My 396 also had 781's with small domed pistons and was a pretty good combo at about 9.2:1 compression.

I have a ported/polished set of 781 head casting I just brought in to have 2.19/1.88 valves put into, and it's not a problem at all.
 
You must log in or register to reply here.

Latest Posts

Top Bottom