StingrayLust

There were a few people on my LGT-700 install thread that wanted some information on the crate engine I decided to go with, so I thought I'd put together one, had been meaning to anyways.

Since I bought my 71 coupe in 2010, I've been slowing upgrading, improving, renewing, fixing, or replacing almost everything on my car except the engine and trans as that just seemed like a huge deal.

Well after basically doing a body-on type resto, the only things left were the #'s matching base 350ci 270hp base engine and the leaky, non-original TH400, the paint, and the frame. Well the paint is in pretty good shape since I drive mine, and the frame, while in good shape, will have to wait until some other time to be fully redone. So that left the motor and trans.

Getting beat by my buddy's C1 and my other friends C3 with a BB, I knew my engine was past it's prime and the TH400 on the interstate was running me past 3000 rpms.

So somehow last summer I convinced my wife to left me change that. So in May of 2014 I ordered the LGT-700 5-speed transmission. Would be sad to mate that to my existing motor so I was able to successfully suggest a new engine. So that trans has been literally sitting in my kitchen since last summer, much to the chagrin of my wife. That's because I pulled my motor in September of 2014 without an exact plan of attack for my engine. Would I rebuild my original, 2-bolt 350? A 383 sounded nice, but once I looked into the rebuild cost, I could get something better it seemed. While I'm in my local NCRS chapter, my car is well past being original, so I didn't really care if my motor was 100% original or not, I wanted some power!

After looking at many options, I took a trip over to see the Tri-Star engine builder right across the border in WI. I liked what I saw and heard so I decided to go with their 406 long block.

So as the process began, I worked with Ben Steine at TriStar to get the details right. I went with the upgrade to a forged crank and the 10.3:1 compression. They list this engine combo as 530hp and 520 torque (street build). Going with the Dart SHP block over my original block seemed like a no brainer with its blind head bolt holes, stroker clearance, 4 bolt splayed caps, Corvette clutch ball location, priority main oiling, and better cooling around cylinder to name a few of the benefits.

The cam was the big undecided. I've seen cars where there was too much cam and hence the vacuum was too low to run all of the vacuum related items on a 71. I wanted to make sure I didn't have that issue. Looking at some dyno test #'s of TriStar's default cam showed about 11hg of vacuum at idle on their dyno sheets you can view online. I read that I should ideally have anything 14 and above for mine. So after much talk and email with Ben and a guy at Howards Cam's I went with the Howards Cam #110255-12, I have a picture below of the card that came with the engine.

Here are the specs as I bought it:






I have a dyno sheet below as well. If I would have done anything different I would have maybe gone up one more camshaft on the aggressive scale, but I'll be fine with my 460hp and 510lb torque!

Out with the old:






New motor delivery:








Decided to get rid of the old valve covers for something shiny. I don't like tall valve covers as they are way too obvious that it's not stock, these are the low profile ones and seem just a teeny tiny bit more stock than talls. TriStar told me the Scorpion rockers would allow me to use these and they were right. These pictures are right after I picked them up from the powder coater (Chevy Orange):




I also decided to use some new pulleys as my old ones were a bit warped and lackluster looking. So I went with these from Ecklers for about $50 total (crank & water). I was told they were a direct replacement for my originals. OMG, HAHAHAHA that's a joke as I found out. My water pump pulley wasn't bad but the crank one was a lot thinner as you can see when I used a straight edge. I also had issues with my new, aluminum Edelbrock water pump as the pilot shaft didn't stick out quite enough for me to feel comfortable, so I had a friends' friend shave just a tiny bit off the top so it had just a bit more meat on it (I think this picture is the before):










I needed some kind of shim, so I Googled around and found this at speedwaymotors.com. They are the the .200" thick version as they have others and fit just perfect, score one for me!!! That spacer also meant that I had to find a new balancer bolt that was longer, went with the longest ARP one I could find that was the black 12pt 13/16".






I also wanted to upgrade the exhaust from rams horns to headers, but needed to be cheap about it. So I went with the Flowtech ceramic coated headers (31106FLT) that others on this forum have used with success. They'll do for now and were about the cheapest I could get into a 1-5/8" header, it's always something I can upgrade fairly easy down the road if need be. You can see that I also played around with 3 different spark plug wire configurations, finally setting on the aluminum ones that hide the wire inside as I liked them best (eBay special):













Seeing as I wanted some things to stay stock, decided that I wanted my vacuum lines to be hooked up as they were before. Problem is that the new valve cover breather holes were too big, but I then found these at Autozone that fit my breather opening outer diameter but had a smaller inner diameter to fit my PCV:



I took it to the Competition Engines in Eagan MN for a dyno session so I would know exactly what I've got, plus I want to get some new stickers that list the HP and torque:







I'll knock TriStar a bit here in that their Chevy Orange paint job was pretty poor IMHO, so I decided to mask it all up and paint it again:



Got me some header extensions so I can feel safe about driving it over to the muffler shop for them to attach the new headers to my existing exhaust and didn't like the idea of that heat directly hitting my fiberglass:



As for my alternator, since they were originally attached to my rams horns, I needed to find a different way. I ended up using the cast iron late C3 version, but I did have to shim it a bit outward to align with my water pulley.

About 2 weeks ago I had some friends come over and we got it all installed in under 2 hours, not bad for my first time.

So there you go, my new engine starter thread. I'm sure I've glossed over something so feel free to ask.

SL

StingrayLust

I forgot to add that I used the Edelbrock Performer 2101 intake.

The TriStar lists the engine as 530hp/520tq, but with my weak intake (worried about hood clearance), my not-so-aggressive cam, 1-5/8" headers, and my qjet, I've definitely left some HP and a slight bit of torque on the table, but I'm fine with that.

I hope I don't break anything after my LGT700 transmission the way it is right now, more hp and tq would only make it worse.

Jbster

Nice write up and pictures! Sounds like a great engine.

FLYNAVY30

cool build, cant wait to see it all put together!

donyue

Nice write-up Stingraylust.

My Tristar 427 is similar to your engine. I made some small changes to the build, like I used a Weiand X-celerator intake, and Dart Pro 1 straight plug heads.

I used Hedman hedders 1-5/8" primary hedders that I had locally ceramic coated and I believe I have the slightly more aggressive Howard's cam as shown below.

Overall I think I want to change to larger hedders and possibly upgrade my exhaust to larger duals, probably 2-1/2 or 3" pipes to the mufflers. Also, debating to change over to side-pipes but that is another discussion altogether.

I think the SS700 trans would be a great upgrade as well but I'm also debating on a Autogear M23 transmission which I think is a little less expensive. Trying to decide if I need the extra gear in the transmission, not sure how much highway driving I will do with the car? Keep us posted on how you like your transmission.

427Hotrod

Those are sweet engine packages. They DO like to breathe with that many cubes.

Here's one we did for a Forum member's car as an article in Corvette Enthusiast. Took everything out of the boxes and screwed it together without too much tweaks. We used the as cast 200cc Dart SHP heads and a custom solid roller from Comp (248"/248") along with 1.6 rockers on intake side.

These tests were with the original 283/270 HP 2x4 intake that we ported like crazy...and it's still tiny! Then we installed the Dart dual plane and a Weiand Team G single plane to really kick up the power. He's been driving it several years and it still runs great.

One thing of note..be VERY careful of the timing curve and detonation. It looks like you stuck with the hypereutectic pistons (I always go with forged for these toys). They don't tolerate any detonation at all...so be careful. Even if you can't hear it..it can be happening.

You're going to have a lot of fun!

JIM

L88Plus

How about maybe when we quote something we don't quote EVERYTHING...no reason for everyone to have to scroll through everything twice.

donyue

Hi Jim,

Looks like you had a lot of fun with your build. I've often thought about switching my Weiand X-celerator intake for a Weiand Team G or an Edelbrock Victor Junior intake but I'm not sure if the small differences would be worth the effort.

Also, I've thought about switching for a Edelbrock dual plane intake but I am a little concerned about the hood clearance. My engine has the fully forged bottom end, I decided if I was going to do an engine swap I wanted to do it right.

Do you think it might be worth swapping out the intake to get a little more torque and HP out of the engine?

Thanks

Don

Kevin BC

Looks like a great build.
Spring is in the air and you be ready to enjoy it soon.

427Hotrod

The latest tall dual planes do a very nice job. The Dart we tested was similar to an Edelbrock RPM Air Gap...and you can see that up to about 4800 RPM it was stronger than the Team G. After that the Team G took over and was up 15-20 HP at the top end.

It all depends on the rest of the combo....if the cam and heads are done by 5500-6000...the dual plane will likely do better on the street. If you're geared and built to spin it a little the single plane will outrun it...IF driven properly.

The X-celerator is OK....but I would expect the Vic Jr to do a little better...as well as the Team G. Not sure if you could tell the difference without serious testing. I'd spend some time with a grinder porting the Weiand and see what happened.

JIM

StingrayLust

Jim,

Actually they aren't hypereutectic pistons. It lists "Forged pistons" on the TriStar site and I even asked Ben this particular question amongst many others and he told me that they use the Icon brand of pistons from the same mfr that also does the Keith Black pistons. You can find a link here.

I definitely left HP on the table with all of my selections, but I'm good with where I'm at, I have to leave *something* to upgrade in the coming years.

427Hotrod

That's good news. The Icon's will take care of you.With a good shortblock...you can keep building and not have to worry about it. Trust me...no matter how much power you have...you'll get jaded and wonder...."what's next?".

At least that's how I've ended up with twin turbos on a 555"!!!

JIM

JimLentz

Nice torque out of that engine.

Jebbysan

Any new pics with the engine in?

Jebby

AboveTheLogic

Those numbers are great!

StingrayLust

I do have it all together now, the engine and the new 5-speed. While I have another significant issue to deal with, something is wrong with my charging system, I did take it out for a cruise today to see where I'm at.

If I start out in 1st gear and get on it, it pulls but not like a train. Now in 2nd gear if I get on it, it really goes once those secondaries open up.

So my question right now, is why my secondaries aren't opening up when I'm in 1st on takeoff? I once did a slow rolling start in 1st aand stomped on it and then could feel the secondaries open as I spun the tires and briefly went sideways.

There's definitely some power there when I can get those qjet vacuum secondaries to open, wow, then it puts a smile on my face. But there are times when I expect them to open up but they don't. Maybe it's the way I'm driving it, or it's just my crappy qjet that I said in another thread that I'm ready to do away with as I've had it.

I'll get more pictures soon, just want to get some details straightened out first.

StingrayLust

While they are good, I went conservative with my cam for vacuum and the intake isn't the best breather, those numbers are low for this engine. The builder using their cam and intake, got 520hp and 530tq, or maybe it was the otherway around.

It's still fine for me, there's some adjustment needed yet for me to get to all of those ponies.

AboveTheLogic

I noticed the conservative specs on the cam, but with those numbers it sounds like you should get a good balance of ease of tuning and pulling good vacuum. My 350 has some sort of radical cam that a previous owner put in and although it is fun, I've had some real trouble tuning the carb properly and getting good vacuum for the power brakes.

71scgc

Lust,

Who's valve covers are those?
Are you using a stud girdle?

Carter

AboveTheLogic

I'm not sure that stud girdles are really necessary with an engine making peak hp in the mid 5,000rpm range. Anyone have any input?