[HWYSTR455]

Very impressive. Maybe the 2800 cam isn't such a pig like I thought...

Still did big valves and good head work though.

.

[Joe-Touring]

Originally Posted by SD455DJ

"The base runs were made with 42 degrees total timing in by 3000 rpm, 45 primary rods/74 jets/CH secondary rods on an I hanger. The 3rd (and best) base pull made a corrected 360.3 hp @ 5000 rpm/456.1 lb-ft torque @ 3600 rpm (351.2 hp/444.5 lb-ft uncorrected). The correction factor was a low 1.026 as the weather conditions were very good...low humidity, high barometer, and very cool temperatures (65 in dyno cell). After rejetting the carb to 40 primary metering rods/72 jets/DA secondary rods on an 'I' hanger (same total timing at 42 degrees), employing the 'big' dyno room dumps for the headpipes, and installing the air cleaner base, the max hp jumped to 371.4 hp @ 5000 rpm/459.2 lb-ft @ 3600 rpm (362.0 hp/447.6 lb-ft uncorrected) on the final pull (#14). The highest torque reading was on pull #13 at 460.3 lbft."

I like this a lot. I can’t imagine anyone being unhappy with 360hp/460tq. Pretty basic parts, cheap and easy. One thing that stands out, I’m not much of a tuner, but 42* of timing is probably the most I’ve seen on here.

I think it’s very tempting to allow a build to snowball and you end up with a very cool and reliable but very expensive engine. I’m certainly guilty of this, the 433 I’m about to start assembling started out as an iron headed 400 build. I got quoted $1200 to rebuild the iron heads, then the quote went up to $2200. So I figured why not spend another $800 for some Alu heads. Then, I have great flowing heads why not add a roller cam for another $1000?

Anywho, I’m sure I’m going to be happy with my 433, but I do think about how a nice basic 400 woulda ran and I probably still woulda been happy.

[SD455DJ]

Joe-Touring, Dan has rebuilt 2-W72 400's and they both made the most power on the dyno with 42 degrees total timing...pulls with 40 and 44 total lost minor power. The large chambers and low compression need a lot of advance compared to the small chamber heads (10.0 & higher SCR's) which vary between 34-38 degrees for best pulls. Every engine's needs are different.

Dennis

[HWYSTR455]

I bet earlier small chamber heads and a .5 SCR bump would have pushed it closer to 400hp.

Wonder if the 2800 cam would still shine in that case?

.

[HWYSTR455]

I bet earlier small chamber heads and a .5 SCR bump would have pushed it closer to 400hp.

Wonder if the 2800 cam would still shine in that case?

.

[geeteeohguy]

I rebuilt the original 400 in my '67 GTO in 1988. Forged TRW pistons, 068 Melling cam and lifters, original Q jet, intake, points distributor. Am running 87cc iron heads (1970 #15) with upgraded screw in studs. This engine has been stone reliable in the 90,000 miles I've put on it since. Last summer, drove it to Colorado on a 2700 mile road trip. Averaged almost 21 mpg (2,56 rear gear) and used between 1/3 and 1/2 quart of oil for the entire trip. I'm at 9.3 CR and it likes 91 octane. This combo, while not a scorcher, has plenty of torque and power, and as the mileage and oil usage indicates, has been dead reliable. Moreso than most new cars. My reliabilty formula for success for all my old cars is stock carburetion, and stock points ignition. I have never been towed due to either.

[SD455DJ]

Originally Posted by HWYSTR455

I bet earlier small chamber heads and a .5 SCR bump would have pushed it closer to 400hp.

Wonder if the 2800 cam would still shine in that case?

.

Dan had the 2800 cam sitting on a shelf for several years and since this was, more or less, a stock style rebuild, he decided to throw it in. The 6X-4 heads are totally stock, except for the new Ferrea 1-ps stainless valves. He mocked the combo up on the DeskTop Dyno where it predicted 350 hp/450 lbft torque. It does benefit from using RA exhaust manifolds.

He also ran DTD's of the 2800, 2801, & 2802 cams in a 400 with stock small valve (10.0 SCR) D-port heads which predicted 341 hp/445 lbft for the 2800, 359 hp/432 lbft for the 2801, and 365 hp/415 lbft for the 2802.

I have a set of '70 #15 heads that have new Ferrea 1-pc stainless valves (1.96"/1.66"), new valve springs and pinned pressed-in studs that I ran on a 455 (+.040") that made 390 hp/512 lbft torque with the 2802 cam/Q-jet/iron intake/log exhaust manifolds. It got 18 mpg in my '70 Lemans 4-dr sedan with a 3.08 12-bolt from a '70 GP. I pulled those heads for 455HO 197's.

Dennis

[Skip Fix]

What did the 197s make?

[SD455DJ]

Originally Posted by Skip Fix

What did the 197s make?

With the untouched 455HO 197 heads (8.60 to 1 SCR)and factory top end (aluminum intake with crossover, 7041263 Q-jet, factory RA exhaust manifolds (with the puny 2.1” outlets) on the same ’70 YH code 455 block with the 2802 cam, it made a best pull of 430 hp @ 5000 rpm and 535 lbft. torque at 3500 rpm.

The small valve ’70 400 with the 2801 cam built to run in the Pure Stock Drags made a best pull of 384 hp @ 5300 rpm and 454 lbft torque at 3600 rpm with 9.94 to 1 SCR and log exhaust manifolds. With any large valve high compression D-port head and RA exhaust manifolds it would make 400+ hp and 475 lbft torque easily.

Dennis

[Skip Fix]

Nice. The round ports-even the HO heads flow a bunch better untouched than the d ports I've flowed do. Using a flat HO valve also picked up flow in RAIV heads.
Buddy just built a 455 with a big dish to use his RAIV heads for a sleeper 70 Firebird. HR cam. he is debating RA manifolds vs some old Tri Ys he has.

[SD455DJ]

Skip,

From what I've seen/read/heard the maximum flow from high compression small valve (1.96"/1.66") heads from '68 to '70 flow roughly 190/145 cfm; the '68 to '70 large valve D-port head all flow in the 205/155 cfm range stock; the 455HO flow in the 230/170 cfm range stock; and the RAIV in the 240/180 cfm range stock. So, the cfm increase from the small valve D-port head to the 197/7F6 455HO head is 40/25, or 21/17%.

The power gains from the dyno pulls between the #15 small valve heads and the 455HO heads on the same short block is an average of 30.0 lbft/24.4 hp from 3000 to 5000 rpm, which seems pretty substantial.

Sorry about the thread derailment!

Dennis

[Skip Fix]

Dennis thanks about the flow difference I have seen with big valve D ports to Ho then RAIVs. Never flowed any small valve. In fact just this week gave the #15s I got off the 455 that is in my 78 30 years ago to a buddy.

I built a low compression 0.030 over 400 with 6X-4s with the Summit 2801 and RA manifolds twin cats(had to pass sniffer then) and a true dual with an H pipe and a 73 Q jet for the 81 TA both my kids drove to high school. dead reliable other than my son(the oldest) never figured out how to drive a carb car in the cold with a choke! His younger sister had no problems. Runs A/C power brakes etc great barely a mild lope.

[unruhjonny]

this discussion, and specifically this post sent me down a rabbit trail which held me up for a couple days;

Originally Posted by HWYSTR455

Very impressive. Maybe the 2800 cam isn't such a pig like I thought...

about my delay in posting - a short while ago microsoft force (another) update, and this time around it removed the ability to open and use several file types - one being spreadsheets;
I had made a spreadsheet comparing camshafts, which I wanted to refer to before posting.
(I hate updates, and the current financial models everyone is using )

Well, today I finally got an xls program, and can chime in on the quoted post.

First: For reasons I don't quite get OE grinds seem to often be maligned, and people's go-to is aftermarket grinds...
I get it, to a point, if you're going to be spending hard earned money, why not go aftermarket if there is theoretical "free" power to be had(!).

The 2800 is essentially a 067 cam with (if my math is correct) 4% additional intake lift, and 9% additional exhaust lift;
According to my info here, the 2800 spec's out as the same grind sold as the Melling MTP-1, and was sold by Nunzie (ect) as the 067HL.

I have long thought that for a good street motor, a 067-068 is about perfect;
Pontiac used the 067 on many mid-performance engines for about a decade, then when emissions started choking things up, PMD went smaller...

The next step down the ladder from the 067 is a 066;
The 066 was generally on daily driver type vehicles - as opposed to performance vehicles where the 067 was the entry level grind used by PMD;
Butler sells the Melling SPC-5 as a 067 replacement, but again according to my information it actually spec's out as being a a hair smaller than the 066 cam.

If you are wanting a street torque motor, and using standard exhaust manifolds, my opinion is that sticking with something around 066-067 duration and timing is what you want - these are great torque cams, and will be happiest chugging along at lower rpms all day long.

If you want a cruiser, and decent mileage, I'd say stick with 2.73:1 or 2.56:1 rear with a non-overdrive transmission - anything more, mileage will suffer.
My 73 Formula ran surprisingly well with the original 2.73:1 rear end in place.