What rpm are you revving your 400 to?
 

See mostly 5500rpm. Anyone go higher? What top end and bottom end combo are you using?
hydraulic roller camshaft?
Dual plane?
cylinder heads?
Connecting rod and piston info?

400s or better said 3.75" stroke and 4.121" bore minimum only please.

The fastest I've spun my 400 to was 6300. I didn't realize it was spinning that fast at the time and will keep it at under 6k from now on, but I know I could get more out of it if I had put a better bottom end in it. I conditioned and peened a set of factory rods and have a nodular crank in the motor with TRW pistons. See my signature for more info on the motor.

I don`t spin engines higher than they make power. I built a 400 PWH engine for a buddies `79 T/A. Stock bottom end. Stock heads with a 60241 Crower cam. I could tell the engine quit pulling after 5200 or so. I twisted it to 5500 a few times. You could tell it wasn`t happy at all there.

I have a 455 with stock rods and TRW pistons also. Larger cam and ported heads. I turn that thing to 5700 to 6000 ALL the time. But, it makes power there also.

So, it`s about the ability to make power at the shift point, then, it will be about the parts strength later. No use building a 7000 rpm capable top end and using stock rods.

I wouldn`t have a problem spinning a 400 with stock rods to 6000 to 6200 or so IF I could make power there.


Aftermarket parts? 7000 to 7500 wouldn`t be a problem for me. We used to turn a 428 with rubber rods to 7000 for years.:eek: Guess we were lucky.:)

In my '69 Bird, the 406 Pontiac - was spun up to 6300 RPM on the dyno (hp was steady/strong at that RPM according to my engine builder). However, the bottom end has had some work done to it (mag'd and shot-peened/polished rods, ARP rod-bolts, a bit of work to the crankshaft, etc., etc.). I likely won't spin it any higher than 6100 RPM. This will eventually be more of a race car (once my GTO is back together) with occasional street use.

For my '72 GTO the rotating assembly is mostly stock (ARP rod bolts, stock crank). I keep a 5800 RPM chip in the MSD - and I believe it bounced off the limiter (once) at the track. This will be a street car (going forward). I won't be tracking this car anymore (unless it is to go through a road-course).

If you do not mind, what camshaft/intake/head combo on the 1969 Firebird to make hp at 6100-6300rpm? I presume you head long tube headers in place?

I ran a RAV 400 Crank for a while with good SD Rods to 7200 with a 255/265 Comp solid flat camshaft and a 850 CFM carb. Custom modded Edelbrock "Don Kennedy style Torquer-1" (Dual Rear Runner sections welded together) with a custom Spacer.
PAC Springs.

Block was my original 64 389 GTO block bored out to a 4.125" bore size. 11.55-117 mph

Tom Vaught

+1. I had a 455 in the car with a smaller comp cam and the car only made power to like 4800. With the HR camshaft that I have in the car now on a 112 LSA and ported heads, the motor will pull really hard at 6300rpms, but I didn't want to destroy the bottom end so I kept it there.

Punch,
Isn't the valve train usually the limiting factor? I was taught that if the iron or steel parts are strong enough, ie forged, the whole problem would be keeping control of the valves. As long as the heads are set up correctly so that the valves are under control, not bouncing off the seats or floating, all is well. Is this correct?

Karl

:usflag:

I have found with back to back dyno testing the dual plane intake is the choke.Even with enough cam a engine setup to make HP to lets say 6800,put a single carb dual plane it might give up at 5800.Put a spcer on it and then maybe 6000,etc.Tom

Forged crank, rods and light pistons, I have my rev limiter set to 6500, shifing at 6300 or so. With the hyd roller and solid lifters, it pulls like a freight train on acid all of the way to shift point. In most instances, it revs so quick, it is hard to keep if off the rev limiter.

Hi RodneyR,

The cam was/is a CompCams P280-H (480/480 lift at .050). I had it at the engine builder due to wiping the original CompCams custom hyd-grind (which was over 520 lift on the intake). The heads were heavily ported #13's (by potentpontiac) which were re-done by the builder with Ferrea valves, a brass valve-seat and a cut (forgot how many angle's he put in the valves). Intake is a port-matched KRE Northwind (with a separate cross-over fabricated up). Right now, given the car has the stock inner fenders, I am using the Hedman 3-tube headers on it. Not sure those would be long tubes.

The engine builder ran it on the dyno with his headers (not sure what they were). Car made 420hp @6300 RPM and 458 ft-lbs of torque at about 4500 RPM.

I am sure if I went hyd-roller (and above 500 lift) the motor will really wake up. However, it is a great street car (enough rumble/grunt) to enjoy. Have not baselined it yet.

A quick video of my car running http://i211.photobucket.com/albums/b...8-13-16-30.jpg

Cheers,
Brian.

Yes, that is a big deal along with the choke that Tom spoke about. The engine design and the lightness of parts is also a big deal. It`s nothing to spin a sbc to 7000 grand with not much fancy in it. It`s guts are much lighter than a poncho.

The Poncho`s biggest problems with revving is the choke factor, valvetrain flex/bounce and the weight of parts. But, they don`t need to rev like a sbc to make power.

By "limiting factor" I meant things not able to mechanically hold up to the rpm if the engine in fact can spin that fast, ie air in and out. If the engine can't get up the speed because of lack of air and fuel, well that takes care of needing a rev limiter doesn't it. :D

Thanks Tom and Punch,

Karl

:usflag:

That is a great "problem" to have isn't it? :D

Karl

:usflag:

The throttle response with the EFI is simply amazing. Floor the gas and the engine goes right to target and makes a butt load of power right now.

With stock rods I limited it to 5600 RPM. With the '62 forged rods ("rubber rods") I took it to 6000 RPM. With my race 400 I shifted at 6800 and went through the lights at 7200. That has Crower rods, Ross pistons and a stock crank.

So many variables to consider that it is pretty much impossible to know what RPM the power is going to stop - and seat-of-the-pants is going to lie to you every time. Big cam with mild heads is going to give up way sooner than a moderate cam and well ported heads. My engine in the Cruiser is a very mellow HR cammed 87 octane 400 with some well ported 670 heads. Doug's headers and ported stock cast iron intake manifold round out the system. The engine was put together before the off-shore aftermarket rods were introduced, so it has prepped stock rods with ARP bolts. Two different chassis dyno's several years apart said maximum horsepower was at 5,900 RPM with a fairly flat torque curve leading up to it. That high of number was surprising considering the compression ratio and cam, but the whole system was designed to let the engine breath. You need to think of the performance potential as a chain with total performance limited by any weak links.

Out on the street through the mufflers the Cruiser runs just about as good letting the 200-4R trans shift by itself at 5,200 RPM - even though the dyno only showed a six horsepower loss through my exhaust. You might be making horsepower at an elevated RPM, but that doesn't mean that you might not be just as quick shifting sooner and letting the converter and the engine torque do their thing.

A converter? On a street car?

At first I was "huh?", then I remembered that you are our supreme leader of 4-speeds forever on the street movement. :p

I have my shift light set at 6500 with the 1-2 shift happening at about 6700 and the 2-3 about 6600. That's where it ET's the best. I can feel it nose over just before the light comes on so I'll say it pulls hard to 6400. I have a 7000 chip in the rev limiter. Stock crank, forged H-beam rods, and heavy TRW pistons. Home ported 670's that flow 245 cfm on the intake, Torker II intake and 850 carb. The cam is a Comp custom SFT 250/256 @ .050 with a 110 LSA installed at 106 ICL.

I forgot to add a smiley face. ;)

Some are just "Natural Gear Rowers", (like OMT) vs natural Chit Stirrers (who typically drive Automatics!) ;)

I row a 5-speed Doug Nash

Tom V.

My 400 Srpint boat engine ran at 6400-6500 for between 55 and 60 seconds at a time.
Took some pretty serious bottom end attention to make it live doing that

D-ports by Jim Robertson (cast iron head rule), Roller cam, offset lifters / rockers, 3/8 pushrods and a big Victor and Bolaws annular carb. Sounsded pretty sweet I thought for a little iron headed 400

http://www.youtube.com/watch?v=3ffCw0rR8pI

BTW, boat guys can shift gears when forced to run on land too (I think)

Tom / Jim, care to "score" my shifting in my street 76 TA with a pump gas 455 ??

http://www.youtube.com/watch?v=CVHEZ77gUxQ

Excellent shifting!

Agree, Excellent Shifting.

Shifts were all high vs the Tach shift indicator needle so assume that the indicator was set 300 rpm low (as you were right on the 6300 mark every gear but first gear. That one was a bit higher. 6500 rpm on a "street 455 combination (was pulling well in each gear) says that you had a nice engine combination going there.

Post up the combination please.

Disappointed that we did not hear the "Bullit Double Clutch" (which I was expecting), LOL

Whoooow, bow, bow, Whoooow, bow, bow, Whoooow, bow, bow, Whooooooooooooow!

(;>)

I had 3 passengers in the car one night and did 3 power shifts. We later went back and measured the spacing between the black marks. Not much space on a properly done Power Shift. Driving some of the Top Loader Trans I can see a Double Clutch situation with those transmissions in a Mustang.

Tom Vaught

This was on a closed course, correct? :D

Karl

:usflag:

Not to hijack the "400" thread, but here goes as per Tom request (all relavent street info :))

Yes I set the tach light approx 300 early, was a bit of a lesson learnt as the the changes (especially 1-2) come arounbd reasonably quick for a street car If you set it where you want to shift you end up over where your rods want to go LOL

Combo was a pretty simple deal I put together to get used to the manual trans before putting a "stout" engine in it and it actually went pretty well for shed parts (11.75 @ 118+mph at 1850kg weight)

455 block + 030, stock 3.25 crank, flat top "heavy" TRW piston, 6X heads (-8) home ported, opened up chamber (2.11 / 1.77 valves) with pushrod sleeve AKA SD heads (Felpro 1223 gasket), Holley SD intake with angle milled welded top section, converted to square bore with 3310 750cfm Holley (stock). I later tried a sleeper look 76 EGR intake with ALOT of internal mods / spacer which would ET the same (due to better 60ft !!!!) but MPH a few less (shifted at 6000 RPM instead). Custom 1-7/8" headers and an HC-03 hydraulic cam. (crane Gold 1.65 rockers)

3.73 rear gear

Pics of the Holley SD 4150 "converted" intake. Would work equally well on a "high winding" street 400. Runners were welded and extended into plenum and a large radius rolled down from the spcer into the runners. Would have preferred a bit more thickness (radius) at the front edge of the runners but run out of time to build up again before testing the thing.

Cutting off the crossover etc allowed for intake manifold changes at the track between rounds, much to the disgust of the Chevy crew watching on LOL

Probably the biggest lesson learnt was match the stuff you are running to the RPM range you intend to run at (or shift where the engine wants it, not where you want it)

I definitly wouldnt have shifted an auto 455 that high but the close ratio box kept the engine up where it seemed happy and I think 4 gears helped this. The manual would have definitly been more suited to a high winding 400 and would have made the starting line a bit easier. The modified factory intake probably would ET better with a 3 stage auto and a smaller cam. When I get some time soon I plan to try this for a bit more "sleeper" look.

Back in the day I used to race with a 400 that had stock rods with nunzi's rod bolts and trws. It was in a 79 trans am, and i used to shift it when the tach read 6k.

Move forward a few years and i had a 455 with the same stock rods that i shifted at an indicated 5,500 rpm.

Then i installed a rev limiter set to 5,500.

Imagine my surprise the first time at the strip when the engine fell on it's face at an indicated 5,100 rpm..... the factory tach was slow to the tune of about 400 rpm. So i had been shifting my 400 around 6,400 and my 455 around 5,900 on stock rods!

Luckily i don't have any two piece rods or blocks with holes in them as a result of that.

7500 RPM
 

389 +.065 (401)
RAIV CRANKSHAFT (donated by the local Pontiac dealer)
455 SD rods - beams polished, shot peened, big end set at lower specs, bushed for .927 pin
Brooks pistons (579 gr with pin)
SK intake with 1050 Holley
RAIV HEADS ported & machined by myself
Lunati solid roller

Shifted @ 72-7300 and went through the traps @ 7500.

When I got out of racing, the FB became a street car for 10 years. Three changes I made was to replace the 1050 with a SK tunnel ram (2 650 DP), install 10 in converter and reduce gearing to 4.88. In that period of time I only put 1000 miles on the car, then parked it in 1996.

When my RAIV headed 400 had a big solid UD cam in it it liked to go to 7000, and had Crower billets to make it there-although a 557 block.