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454 build up

15K views 56 replies 8 participants last post by  Horsepoweraddiction 
#1 ·
I'm hot ridding my 85 gmc Sierra with a 454! I need some tips on what to get next because I already bought a cam and a set of hooker headers. It still has stock manifold and quadrajet carb, the cam is an xtremeenergy xe274h-10
 
#31 ·
You need more gear and compression for a 500hp 454 in a heavy truck.

The cam you have is already too much for a 2.73 gear and compression in the mid 7's. And tall tires will make that worst. Plus a higher stall converter will be needed.

If you don't plan to increase compression, add more gear and higher stall, then add boost to make your HP goals. And use a smaller cam that matches the gear and stall.
 
#33 ·
3919840 heads

The 3919840 heads are 1967-69 396/375hp, 2.19/1.72 valves, 106.8 chambers. If the exhaust valve is 1.88 they are 1967-1970 427ci heads. Check them out on ebay. Complete they are selling for $1000-$1500. They are a closed chamber head but would work on a 454 with flat top pistons. You would have to check piston to valve clearance. Compression ratio 8.912.
 
#35 · (Edited)
Yeah I have flat top pistons and I'm sure they will work because the guy I bought it from was planning on putting them on a 454 , And would that compare with a set of the 781's heads? What could I do to get the compression higher?
If you could find a set of 781 oval port heads they are open chamber and 113cc. They could be milled but how much??? The compression would still be low at 8.5. I wonder if a set of [10141279 1996-up, Open 100cc Vortec7400] would work like Vortec's do on small blocks. Compression would be 9.4. Another Vortec Casting # 12560241 1998 -up, Closed 100cc Vortec 7400. Close chamber heads that would work are 3872702, 3904390 98.4 cc, compression 9.5. Checkout ebay http://www.ebay.com/itm/1973-1985-B..._Accessories&hash=item56499a68ff#ht_500wt_969
 
#37 ·
You know they have to many websites that have the wrong information. I just looked that info up last night on nastyz28.com. 454C10 would you be able give an answer. Will the 454 Vortecs heads work on the early bigblocks with flat top pistons like they do on early small blocks? Anybody else?
 
#38 ·
I run a set of 781's on my 454 and they are 120cc. So, I didn't need to look it up in this case. I also use a small dome to get it up to 8.75:1. Flat tops are the stock smogger piston in a 454.

I also have a set of 820's from a 73 402, and they measure 112cc. These are also good heads that would increase the compression in a flat top 454.

I heard the votec head will work on old BBC blocks, but I have no experience with those. I also read they are good heads and the low engine output from vortec 454 is due to the poor cam and intake.
 
#43 ·
You don't need anything special. Just a plain hyper pistons would do the trick.

If you are still planning on using a xe274 cam then look for a piston that will make 9 to 9.5:1 cr i a 454 with 120cc chambers (781 heads).

I recommend the old school 280H cam if you go with a flat tappet cam, as it is less likely to go flat than the XE cam.
 
#46 ·
Generally forged are heavier and run a looser piston-to-wall clearance. But there are lightweight (or lighter weight) forgings that run tighter clearances than some of the old style forged pistons.

But there's little if any difference in the actual performance between the two if they are both set up properly- at least until the cast/cast hypereutectic piston reaches the point of no return, a point which will be found sooner than a forged piston. Just be sure to fully warm the engine up before hammering on it w/forged pistons. That gives them time to expand closer to their running dimensions where the ring seal will be better because of less piston rocking.

But if you plan on nitrous, forged gives a lot more leeway in case of detonation. Detonation can kill ANY piston when running nitrous, but a cast hypereutectic piston will literally shatter whereas a forging will tend to go down in one piece for the most part unless the detonation is ignored. And it may even survive if the detonation isn't that severe.

Nitrous is very demanding on an engine. Aftermarket rods might be in order because I do not know of anyone who has been satisfied w/a "small" shot of N2O. At the VERY least, the rods need to be magnetic particle inspected, new ARP hardware installed, and then resize them. There are ignition boxes that will pull out timing to keep the engine safe; if I were to build a serious nitrous engine, you can bet I would be running one. Not really necessary at the lower levels, but even then the timing can be run higher when not using nitrous- which equates to better performance when on or off the bottle.

When you get to the >250 HP stage, think about better rings/ring material. Even at low doses, plasma moly is the minimum because moly inlay can chip off the ring. 250 HP and up forged isn't an option IMO, although you'll hear guys who get away w/it. Trouble is there's NO leeway if the tuneup is off, or a fuel pump problem comes up or for any number of things.

This barely scratches the surface but will give you some things to think about. There are guys here w/more experience using nitrous than me, hopefully they will be along shortly.
 
#50 ·
550hp is my goal.
Don't be so focused on a certain peak HP number.

Trust me, you will be happier with a strong torque engine that pulls hard from down low through the midrange. That is what you "feel" when you nail it.

Throttle-response and torque gets you rolling.

I would rather have a Big Block that makes 500 torque at 3800 RPM and 480hp at 6,000 than one that makes 200 torque at 3,500 RPM and 520hp at 6,500.

You just pick your tire size and rear-end gears to match the torque curve, and you are all set to rock. You don't have to run as much converter stall either. It's a win-win deal.
 
#51 ·
Man you are right and nitrous would do what i needed it to do at times. but i own 3 454s and they need building haha. but for the one currently in my truck i am satisfied with it 'for now' but i will build me one with mech roller and so on and so forth. i'll further gather my knowledge and see what i come up with man. Thanks for commenting man. i got this 496 i been wanting to build haha.
 
#54 ·
LOVE the 540. Love the 632 even more.
But now you are in the world of big-money. Can't get 540 cubes from a stock 454 block.

And with that many cubes, big port aluminum heads are a must.

Only problem with running bigger than a 502 on the street is the darn things drink GAS! I love big-inch motors, but you can't drive past a gas station.

Gotsta keep it "streetable".
I doubt I could get a 632 to hook up on the street anyway.
( Funny car slicks with some grooves cut in them? )

:D
 
#55 ·
The 540 option is like the 434 option in small blocks,the price is decent,you dont have to use a tall deck like the 632, street able 675 hp 540s are common and can put any car deep into the 11s. all with a single 850 and hydraulic cam.
Gas mileage is figured by sfc and gearing/average speed,,,,,,etc. Gas consumption will start at lots and go upwards
 
#56 ·
Horsepoweraddiction, You say you have (3) 454 motors. For now build a mild streetable 454 for your truck. Take a block, crank, rod & pistons, and your 781 heads to the machine shop. Have the machinist check the block, then have it dipped, bored & honed, install new cam bearings, freeze plugs, screw-in oil gallery plugs, and deck the block. Have the crank checked, if ok have it polished. Have the pistons removed from rods, install Arp rod bolts and then have rods resized. Purchase Keith Black Icon Forged Pistons part# IC779 at CNC Motorsports for $510.95, Jegs $649.99, Summit Racing $719.95 and have them installed on rods. Have your heads checked out and don't forget to have the matching springs for your XE274H-10 camshaft installed. With a build like this it will be strong enough for the 100-150 shot of nitrous to get you to 550hp.
 
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