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Big block guys

I guess I'm going to be building this thing. So I need some opinions.

First, the overall goal for the engine is to put it in my blazer and have it do anything I need from being a DD, driving it on road trips for 100's of miles at a time, to do any type of wheeling I may come across. I'd like around 500 hp and 500 ft lbs of torque at a low rpm, since I don't really get the RPM's up too high with the 350 now.

I want to get rid of the dished pistons and get either flat top or a small dome piston. I also will need a new cam, does anyone have any suggestions other than the one Zim posted? Any suggestions on an intake that'll match the cam power range? Then, for now I guess I'll put a carb on it until I can scrap up enough cash to do something like atomic efi or ez efi. I've got an edlebrock 1405 from my 350, but I'm sure that's not enough for the 454. I just talked to the machine shop and they quoted me $425 to do all the work to put the bigger valves in the 781 heads, but need to at least nail down what cam I'm using so I can bring the valve springs with me to the shop.

Another question that I've been thinking about. Since I'm running TPI right now I have the fuel pump in the tank that puts out something in the 50 psi range. Is there a way to use that fuel pump and be carburated?
 
It would seem to me that you could run that pump as long as your regulator has a return line, that's basically what I'm doing except I have a TBI pump.

I would think 500hp might get a little choppy to be long distance travel friendly. I'm sure you've seen the specs on my motor (build thread post #488) and I feel comfortable saying it's a 400hp/500tq motor, it's got a little lope to it but still very user friendly. It's not for everybody (and machine shops can't always grasp it) but don't dismiss keeping the small valves for low rpm torque. It's not a popular option but if you can figure out a way to make those power numbers without forcing it to go to high rpm (5k+) that would be money saved for something else.
 
What about some 22cc dome pistons to bump compression up to around 9.5:1?
 
That's what I used, Speed Pro hypereutectic h693cp with 22cc dome. The machine shop said with my heads they should yield 9.4:1 comp.

After the fact, I wish I had gone with forged but only because I spent a ton on everything else so why cut corners there.
 
With big valves your gonna want at least 9.5:1 compression. A lot go's into compression ratio so your gonna wanna find your pistons last. The extreme 4x4 cams are the best bang for your buck for on street & great low range HP/TQ. A good dual plane intake and a truck avenger would be a great setup.
 
I have had a few 454 engines, and the ones I had in 4X4's got about the same mileage as you are getting currently with your small block (7.5 miles per Gal.), but the ones I had in 2-wheel drive trucks got about 10 to 12 miles per Gal.
 
My best 454 engine was in a 1977 C30, Duallie, single cab. I rebuilt the trucks original 454 in it. I put flat top cast pistons (roughly 8-3/4:1 compression), the original stock 76cc open chamber oval port heads (new valves and Blue Racer springs), blue racer RV cam (.490 lift/295 ADV. duration), balanced, Edelbrock intake, Carter AFB 750 CFM carb, Holley electric fuel pump, headman headers, custom built dual exhaust (3" pipe with cross over), and backed up by a freshly rebuilt Turbo 400 with a shift kit.

This 454 could go 80 MPH on the open road for hours with out even trying hard. It could get as much as 11-to-12 MPG on the open road, but only about 9 to 10 in stop-and-go.
 
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My engine shows 560tq on the engine dyno 2000 computer program....not sure if its right or not, but I never hurt for power.
I'd say don't worry about a HP number just shoot for a nice flat torque curve...my engine shows 500 torque from 2000rpm to 4500. (not sure what it is below 2000, as that is where the dyno program starts) Use a small domed piston (SRP's) that ended up at about 9.4 static and with my cam was less than 8:1 dynamic...I ran a JET quadrajet (http://jetchip.com/shop/performance...ig-block-quadrajet/rochester-big-block-q-jet/) and ended up changing to FAST EZ EFI. I still have the carb but it needs a rebuild from sitting for 4 years.
 
blazinzuk said:
I agree with Dave. Build for a nice flat torque curve. It will make for an enjoyable motor.
Click to expand...

I'm with deez guys.

My 383 in the Beaumont pulls 400+ foot pounds from 2500 to 5600 according to a desk top dyno. It feels like it could pull a house no problem.
 
Why are the engine dyno simulators all so stupid?

I hate how the X/Y coordinate scales are always set to some default setting like (1000HP and 11,000RPM) and can't be changed by the user to something more useful.

The "actual" data you want to see ends up as a tiny little portion of the graph that's hard to read with any accuracy.


-G
 
Greg72 said:
Why are the engine dyno simulators all so stupid?

I hate how the X/Y coordinate scales are always set to some default setting like (1000HP and 11,000RPM) and can't be changed by the user to something more useful.

The "actual" data you want to see ends up as a tiny little portion of the graph that's hard to read with any accuracy.


-G
Click to expand...
Not much is going on under 2k that's why & anything over 1000hp is getting after it. This isn't a dead nuts thing, it's just a tool to help you get a round about estimation....
 
Hoss7979 said:
Not much is going on under 2k that's why & anything over 1000hp is getting after it. This isn't a dead nuts thing, it's just a tool to help you get a round about estimation....
Click to expand...


I understand.

It's just poorly written software and something that has been wrong for MANY years with engine simulation programs that I've seen and used.

Graphs should be "scaled" to the specific engine that is being simulated (or at least have the option to scale properly)... instead of putting every engine into the same 11,000RPM / 1000HP scale.


-G
 
Greg72 said:
I understand.

It's just poorly written software and something that has been wrong for MANY years with engine simulation programs that I've seen and used.

Graphs should be "scaled" to the specific engine that is being simulated (or at least have the option to scale properly)... instead of putting every engine into the same 11,000RPM / 1000HP scale.


-G
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It's only $52 for the basic software......it's not CAD. I would assume if you went w/ the more expensive versions you'll be able to do more! :thumb:
http://www.summitracing.com/search?...ch&SortOrder=Ascending&keyword=dyno simulator
 
I guess I'll put a parts list together so y'all can critique it.

Cam that Zim recommended. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=468&sb=2
Valve springs. http://www.summitracing.com/parts/cca-911-16
Rebuild kit that has gaskets, bearings, oil pump, etc. http://www.ebay.com/itm/121963784479?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Pistons. http://www.ebay.com/itm/171981125763?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Balancer. http://www.summitracing.com/parts/sum-162454/overview/
Flexplate. http://www.summitracing.com/parts/sum-g102sfi/overview/
Headers. http://www.summitracing.com/parts/hok-2463hkr/overview/
Intake I'm looking at, but haven't looked much. http://www.summitracing.com/parts/edl-7561/overview/

Still thinking about the heads. If I don't get them opened up for the bigger valves, then I'll just leave the smaller ones in it and run them like they are.
 
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I have the 262H cam with 4.11/Th400/39.5" TSL. Pulls fantastic for mud, snow, daily drive. Daily driver excellent. Engine all stock with low 7.8cr.

My friend has the 268H you linked to, with 4.11/Th400/36" TSL. Pulls fantastic also. Daily driver excellent. Pretty well stock also.

Both cams are great choices. The headers should help too. Only reason I haven't gone headers yet is I have a PTO winch .
 
It all depends on how much you honed out and if the bore is straight...might have to get some oversized pistons. I would recommend a bigger cam. I've had 2 extreme 4x4 cams now and they work well in heavy vehicles.

I have a buddy that runs this intake and likes it.....http://www.summitracing.com/parts/sum-226020/overview/make/Chevrolet

I would try and get 1 7/8 to 2" primaries for your headers instead of 1.75'

With that setup you stated your looking around 400hp @ 5k and 498tq @ 3k just by running the numbers on desktop dyno. With bigger valves your gonna gain some...436hp @ 5k and 506tq @ 3500. So you have to weigh your cost to gains.
 
Also, I don't know anything about converters. Well, I know generally how they work, but nothing past that. The 268 cam says I can run a stock converter and I'd have to get a 2000 stall converter with the 270 cam hoss recommends.
 
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