400 build

[gwcrim]

Since the heads are on order, I've turned to focus on cam selection.  Today I called Howard's and learned something.  As John and I discussed my build, his biggest concern was not the converter stall speed but the overall top gear ratio.  With 3.73s and a 0.7 overdrive (and a 26" rear tire) when the trans goes into overdrive at around 45 MPH, the RPMs will drop to 1500.  If I go to a 28" tire, it's 1400.  A big cam wouldn't like that.  John said if it wasn't for the overdrive, I could run any cam I wanted.

So..... 3.73 is too much gear for no overdrive and not enough gear to overdrive.

OK, actually the cam recommendation was either 110041-12 or 112571-12.  The wider lobe separation and modest lift should keep everything happy.  I'm not ready to commit yet, but the picture it getting clearer.

[Engineer]

I generally never make cam recommendations because it is too easy to select the wrong cam and there are too many profiles available that makes an error possible.

With that said I feel comfortable making these general statements about cams.

I didn't look at those profiles but as a rule more cubes will allow you to run a little more cam, and you are there with the 400.

If you were running a 327~350 I'd recommend the smaller cam.

[gwcrim]

Actually, the duration of each is about what I was thinking.  One is 215/225 and the other 225/235. The surprise to me was that both have 112 degrees of lobe separation.  They are probably both conservative recommendations.  No one wants to have an unhappy customer.

With a switch for converter lock up and keeping it in drive around town, it seems like a pretty decent set up.   I think I like it.

[gwcrim]

Pushrods and rockers. What do I need?  I'm leaning toward1.5 full rollers.  The 465/488 lift is good enough.  Since I'm not intending to swing this past 6000, standard pushrods ought to work.  The block appears to have never been decked.  I love that its all coming together.  Today I decided I need to put the new dash and tach in before I install the new engine.  I'd like to be able to keep an eye on things during the initial fireup.

Now looking into whether I should leave the TH350 in at first so I have less to adjust and install.  Or maybe just bite the bullet and do it all together.  Decisions, decisions.

[gwcrim]

The Promaxx heads came in last week.  Nice, shiny new aluminum heads!  The edges of the chambers were quite sharp so I took a cartridge roll to them.  Didn't really remove much material, just took the edge off.  Unfortunately, when I sat them on the block I found that the dowel holes are about 0.5mm too close together.  Before I start on them with a die grinder, I'll call Promaxx just to see how they might recommend fixing the issue.

After a bit of thinking, I decided it would be best to take the bottom end apart for cleaning and inspection.  There was a bit of crap accumulated around the rings as I expected.  The engine sat in a not so clean garage, uncovered, for quite a few years.  The pistons got a kerosene bath and cleaned up very nicely.  There are still paint stripe marks on the second rings.  The top end is in very nice shape.

At first glance, the crankshaft isn't so nice.  I noticed spotty wear on the rod bearings.  Almost like there had been dirt run through.  The #1 main bearing appears to be worn at the 12 o'clock area much more than you'd expect considering the condition of the pistons and rings.  I miked it and it's already been cut 0.020 and some of the journals are a little rough and maybe beyond service.

The crank will go for inspection and balancing if it's usable.  If not..... new crank time.

[gwcrim]

So I took the whole she-bang to a builder.  Those guys move s-l-o-w.  I took it there 12/29 and it's not done yet.

Upon inspection, the crank was on it's last leg.  Turned 20 already and right at minimum spec.  The rods were stock 400 rods (as I was told when I bought it).  Here's the interesting part.  The pistons were for 5.7 rods!  As I stood there talking to Doug when I dropped it off, the light bulb came on.  If the pistons were wrong, that would explain why they were down in the whole so far.  He confirmed that. 

In February, he ordered a rotating assembly with 5.7 I beam rods and dish pistons.  We're going to do crank, rods and pistons.  WTH, why not?  In for a dime, in for a dollar.  He's trying to get a few other engines done and I'm running out of patience.  Like that will accomplish anything. 

I also took the heads to him for disassembly and inspection.  Might as well.

Hopefully, sometime in May.

[HAULIN IT]

Something seems wrong with the whole piston deal...The 400 rods are .140 shorter than the 5.7" ones. The pistons for 5.7 rods on 5.565 rods should have put them nearly .100 more (almost 1/8") in the hole than you were measuring.

I wonder what cc's the heads were that were on the engine before? With 2 valve relief (5-6 cc's) flat tops, that bugger would have some serious compression (10.5-11.0?) even .045 in the hole if they were 64cc like many Brodix heads are...maybe piston slap/detonation was the noise he was hearing? Lorne

[Don5]

Pushrods and rockers. What do I need?  I'm leaning toward1.5 full rollers.  The 465/488 lift is good enough.  Since I'm not intending to swing this past 6000, standard pushrods ought to work.  The block appears to have never been decked.  I love that its all coming together.  Today I decided I need to put the new dash and tach in before I install the new engine.  I'd like to be able to keep an eye on things during the initial fireup.

Now looking into whether I should leave the TH350 in at first so I have less to adjust and install.  Or maybe just bite the bullet and do it all together.  Decisions, decisions.

I have a 355 with a 480 lift cam in it. I also started out with stock pushrods and rockers. About a month after I put the engine in, it sounded funny one day so I pulled it into the garage and took the valve cover off. I had a pushrod that was missing! It was laying down under the intake. I checked the rocker arm and it had 4 small cracks right at the stud. When I pulled the pushrod out the end was mushroomed a little. I replaced the pushrods with hardened ones. I also replaced the rockers with stamped long slot steel 1.6 rockers. I couldn't afford the roller stuff. No more problems though. I considered it cheap insurance. The heads are stock also.

BTW- Intending on not pushing past 6000 rpm. From an ex drag racer. really? Come on.. I pushed my 400 on a regular basis up to and beyond that. Of course I was street racing too. I don't think I could get away with that anymore around here. 

[Don5]

Something seems wrong with the whole piston deal...The 400 rods are .140 shorter than the 5.7" ones. The pistons for 5.7 rods on 5.565 rods should have put them nearly .100 more (almost 1/8") in the hole than you were measuring.

I wonder what cc's the heads were that were on the engine before? With 2 valve relief (5-6 cc's) flat tops, that bugger would have some serious compression (10.5-11.0?) even .045 in the hole if they were 64cc like many Brodix heads are...maybe piston slap/detonation was the noise he was hearing? Lorne

I am not sure about the stroking on a 400 and I could be wrong, probably am, but I wonder if this is a 377. That is a destroked 400. They are said to hold up to 8000 rpm pulls all day long while producing great torque. Someone with more experience can weigh in and correct me if I am wrong. 

[Don5]

Pushrods and rockers. What do I need?  I'm leaning toward1.5 full rollers.  The 465/488 lift is good enough.  Since I'm not intending to swing this past 6000, standard pushrods ought to work.  The block appears to have never been decked.  I love that its all coming together.  Today I decided I need to put the new dash and tach in before I install the new engine.  I'd like to be able to keep an eye on things during the initial fireup.

Now looking into whether I should leave the TH350 in at first so I have less to adjust and install.  Or maybe just bite the bullet and do it all together.  Decisions, decisions.

I have a 355 with a 480 lift cam in it. I also started out with stock pushrods and rockers. About a month after I put the engine in, it sounded funny one day so I pulled it into the garage and took the valve cover off. I had a pushrod that was missing! It was laying down under the intake. I checked the rocker arm and it had 4 small cracks right at the stud. When I pulled the pushrod out the end was mushroomed a little. I replaced the pushrods with hardened ones. I also replaced the rockers with stamped long slot steel 1.6 rockers. I couldn't afford the roller stuff. No more problems though. I considered it cheap insurance. The heads are stock also. My thinking is that with a cam of 480 lift I would replace both.

BTW- Intending on not pushing past 6000 rpm. From an ex drag racer. really? Come on.. I pushed my 400 on a regular basis up to and beyond that. Of course I was street racing too. I don't think I could get away with that anymore around here.

[gwcrim]

Something seems wrong with the whole piston deal...The 400 rods are .140 shorter than the 5.7" ones. The pistons for 5.7 rods on 5.565 rods should have put them nearly .100 more (almost 1/8") in the hole than you were measuring.

I wonder what cc's the heads were that were on the engine before? With 2 valve relief (5-6 cc's) flat tops, that bugger would have some serious compression (10.5-11.0?) even .045 in the hole if they were 64cc like many Brodix heads are...maybe piston slap/detonation was the noise he was hearing? Lorne

HHHmmm.........  Those dang decimals........    I see what you mean.  Regardless, the engine will be blueprinted so everything will spec out.  We're shooting for 9.5:1 or so.

The PO used Brodix heads of some sort.  He really wasn't very savvy on engines

[HAULIN IT]

I am not sure about the stroking on a 400 and I could be wrong, probably am, but I wonder if this is a 377. That is a destroked 400. They are said to hold up to 8000 rpm pulls all day long while producing great torque. Someone with more experience can weigh in and correct me if I am wrong. 

Don, The 377 is made by using the 3.48 (350 ci) stroke crank in the 400 block. If it was 5.7 spec. height pistons with 5.565 (400) rods it would be WAY deeper in the hole due to the much shorter stroke compared to the "original" 3.75. Following me? If the pistons are for a 5.7 rod...they would be shorter than the original 400 ones. If the rods are original length (5.565) connected to an even shorter than original stroke crank, he would be over a 1/4" in the hole.

I would think some more (re-checking) measuring would be in order. The .040 in the hole doesn't surprise me if the block hasn't been decked. A couple thousandths off the rods during reconditioning added to the original amount & really I could see the collection of parts being correct. On another note, not likely due to the nature of the 2 valve relief flat top piston...but many "rebuilder" type pistons are made with a shorter height to keep the compression ratio the same after the over bore operation. Lorne

[gwcrim]

OK, well.... It's been a hellova year.  Had a fire at my house and toasted all my belongings.  Fortunately, the engine was at the machine shop but I did lose a fair share of parts.  We're back in the house again and the engine is almost done.  I let him put it off until the beginning of the year since I was out of my house for 6 months.

Many changes have happened since my original idea of building a budget motor.  The whole rotating assembly is new and blueprinted. Compression is around 9.5:1.  The Promax heads were blueprinted as well.  There was some slop in the guides.  Went with a Comp roller cam and rockers.  It will be topped off with the RPM Performer intake and a new 83770 Holley.

It's should be done this week.  Now I have to come up with a transmission.  A local shop wants to do me up a 200R4.  That's probably what I'll choose.  Keep the stall around 2000-2200.  Doug the engine builder says it will make 350 lbs of torque around 1700 RPMs and build from there.

[gwcrim]

I thought I'd post a pic of the final result.  Thank you all for those who answered my questions. 

It's got the Promax heads, 9.5:1 compression, small Comp Roller cam and roller lifters, Performer RPM intake, and a 770 Holley.  Topped it off with a dual, fresh air snorkel.  Still messing with the timing.  Using an Accel hi-po replacement distributor.  Total timing is about 35*.  Have to set the idle timing.

Trans is a 200 4R with a mild build from a local repair shop.  I'm not crazy about it but I'm a stick guy.  It shifts pretty well under normal driving but not quite so well if I stomp on it.  TV cable is taut at WOT and I used all the correct Holley bracketry to set it up.  If it gives me trouble, I'll take it to a specialist.

As of now, it drives pretty well but there's a slight stumble at steady throttle and off idle.  I think it needs more advance.  I believe the jetting is right.