[tr709]

All,

Just not happy with the new motor in my 67. Not making nearly the power it should and can't even break the tires loose from a dead stop. Car is a cruiser and not a race car, but I would like to have a little fun now and then. Motor has 500 miles on it and way to much money invested to perform like it does.

Combo
72 400 block w/428 rotating assembly from PPR
D-port 96 heads rebuilt and ported by butler
comp cams hyd roller XE276HR (yes the same cam that has been the subject of much discussion here) - 276 I - 282 E 224 I - 230 E .502 I - .510 E
q-jet - rebuilt by Cliff
performer intake
pertronix ignition 12 deg initial 36 total - all in by 2500
stock exhuast manifolds into duals with flowmasters
2200 stall (unknown mfg)
Turbo 350 - 2.93 gears

So here are my options as i see it
Since lots of folks hate this cam, go with a custom grind (since I have my head flow numbers) or a recommendation from here
update to long branch exhause maifolds to take more advantage of the head work (not sure how much I'll pick up there)
Different converter/stall to better match the current cam - agian not sure of the gains possible.

Help please?

[68WarDog]

Your combo looks sweet for a street cruiser.And I have to disagree regarding the XE276HR being the subject of much debate.Maybe the XE274?But I digress. With you present cam and setup,the only fault that stands out is the 2.93 gear. IMHO that cam needs something in the 342-373 range in a 400 with approx 24-2800 "quality" stall converter. I have a friend with that same cam in a .030 o/b 400 ,box stock 87cc E-heads,1 3/4 doug's and 2.5 full exhaust , with a B&M 24-2600 stall(hole-shot) and 373 gear and it absolutely rips from a standstill.

OOPS; I see where this is a 428. Still think needs at least 323 or better yet 331's for a 428.

[Cliff R]

Do you plan on upgrading the converter and/or gearing? A good torque converter would be a tremendous upgrade for the combination, allowing the engine to quickly rev into the good power range. The gearing is OK, but not optimized for best vehicle performance.

As for that particular cam, I've had the opportunity to tune several Pontiac 455's using it, and it just isn't a good choice, IMHO. Not sure how it would fair in a 428 build?

The Performer intake is also a restrictor plate for the cid and ported heads. My last 455 engine wouldn't even run with one in place, and it only made 494hp.

We built and tested a 428 here couple of summers ago, with an iron intake/q-jet and unported KRE aluminum "D" port heads, it made 497hp and over 530ft lbs torque. We used a small HR cam, 236/242/110. Even with that much cam in it, quite a bit larger than what you are using, it idled nicely with 12" vacuum, and made strong power to 5600rpm's.....Cliff

[OINK 1]

It's the rear gear ratio ! For GOOD all around performance and good highway, get 3:55's if it's a 12 bolt, 3:42's if it's a 10 bolt.
What kind of exhaust manifolds, Stock ? or Ram Air 3 ? If stock, that's a BIG problem....
Like running your car with a potato stick in the tail pipe. Remember doing that to the school bus ?

Pontiac Gregg

[i82much]

I say give it some gear. A lot of people like a nice lazy cruise rpm but I say who cares. Back in the day there wasn't a hot car out there with an overdrive, and they all had 4.11's, .33's, .56's. Why not run a 3.55 or 3.73 gear? Yeah it'll be a little buzzy on the freeway but just slow down and enjoy it.

[tr709]

Thanks for all the input so far

Cliff - read your posts about the cam, after the motor was already in the car of course.

On gearing, a bit nervous on that as a lot of my cruising is on nice 2 lane stretches out in the country where the speed limit is 60-70.

On converter - really thinking about that, but do I need to go custom, like a continental for my needs?

Basically looking for best bang for the buck for say $1000-$1500 w/labor.

Thanks!

[PONTIAC DUDE]

Motor combo looks good. But those Tennessee road gears would kill any mid modified engine combo. Ya ever watch the NASCAR green flag acceleration at Daytona. Same deal.

Ya want the best deal. Install a 3.55/3.70 gear and a overdrive tranny. (Just like the 1993 & up GM cars)

A properly build 200R4 will hold up and bolt right in. Just a shifter the crossmember change. Go to a 2500 stall.

[gtome]

Somthing just doesnt make sense here?? With that engine, even with those tall gears it should destroy the tires from a standstill.

[68lemans462]

Get a good converter and increase the gear and your car will wake up big time! I run 3.42's in both my cars and I love this gear ratio. Good on the highway and enough down low to have some FUN!

[tr709]

Somthing just doesnt make sense here?? With that engine, even with those tall gears it should destroy the tires from a standstill.

I agree!!! Heck the old tired 350 that was in there before w/the same gears would smoke em better.

[guccieng]

it's the gears. for my performance car, i've got a ford 9 inch with 3.70 gears, and cruise on the freeway 80-90 mph. i'm turning almost 4000 rpm for a 52 mile one-way trip to work. it's not that big of a deal. it's not miles per gallon, it's smiles per mile!

[ta man]

Does the engine perform poorly at all rpms?Did you degree your cam?Have you tried more ignition timing?

[tr709]

It runs smooth at all RPM, just not enough power. Doesn't feel much over the 350 it replaced. When I asked about the cam, builder replied straight up. I don't have the know how to check the cam degree, but I have wondered about it. The dist was just rebuilt and recured to have timing all in by 2500 rpm, any more than 36 degree causes detonation.

I have struggled for 6.5 years with multiple shops in this area, I know now why most of you diy.

[Ron H]

Good questions TA man.

It's obvious. No one can stress about more gear and bit more converter than has been done. 3.42's would wake it up and still be good on the highway.

You never answered on the exhaust question.
What size pipes and mufflers?

[tr709]

exhaust is duals with stock manifolds and flowmaster 40's (was in my combo at first post). Pipes are stock size.

I realize long branch mainifolds would help, but I have to wonder how much given the cost

mainfolds(coated) from RARE approx $600
labor to install $400 (quoted)
new downpipes will be needed cost ???

so I'm looking at at least $1200

based on what I am hearing, maybe start with a higher stall converter? I'm ok with a phased approach, agian looking for bang for the buck.

Thanks!!

[Kyflier]

Hedders would be a cheaper alternative to manifolds. Buy a good set, they will seal better and lost you a long time. They should also help with power. The cam degree was a great suggestion, but other things seem amiss here as well. You said stock pipes, that would be 1 7/8 or 2" which would also choke a big motor too....

[amcmike]

C'mon a 428 with a 224/230 on 110 hydraulic roller and performer intake can't get 2.93s to spin? Something isn't right with the engine. Sure, the gears aren't the best, the exhaust is restrictive, and it could use a little more convertor, but it should still get up and go.

You need to start doing some basic investigation like compression test, take off the valve covers and make sure everything is moving ok. Look at the spark plugs. Recheck your cam timing with a degree wheel, etc.

Your exhaust is definitely going to need to be upgraded to really take advantage of the rest of the components. Upgrade to long branches, 2.5" duals witha Xcrossover, and get rid of the slowmasters.

I'd say do the basic checks first, if you dont' find anything, upgrade the exhaust (might as well do it before the next step, if you're going to do it), try adjusting the carburetor and ignition timing. If you don't know how, or doing it doesn't get you anywhere I'd suggest finding a reputable dyno facility.

If you can get the engine running proper and little more convertor, you can keep the 2.93s and have plenty of fun.

[amcmike]

Originally Posted by tr709

It runs smooth at all RPM, just not enough power. Doesn't feel much over the 350 it replaced. When I asked about the cam, builder replied straight up. I don't have the know how to check the cam degree, but I have wondered about it. The dist was just rebuilt and recured to have timing all in by 2500 rpm, any more than 36 degree causes detonation.

I have struggled for 6.5 years with multiple shops in this area, I know now why most of you diy.

Straight up, means he lined up the gear dots instead of using a degree wheel. Cam could be off. Relying on the dot method is roulette.

[Gach]

2.93 gears...that's you number one problem, get rid of them and put a converter in
to match were it's make peak torque. Then the thing will fly.

[Jagtec1]

Toss those gears. 3.55, and roast 'em. I had a 2.56 gear in my car at one point. Went from that to 3.55....WHAT A DIFFERENCE!!! A converter/gear change will really wake it up.