377 sbc opinons please.

rider8699 · Post by **rider8699** » Mon Sep 22, 2008 8:05 am

Hi all. First post on the forum,but I have been lurking here for a while,and have learned a lot from the pros on here. I have a 511 casting four bolt main block, a gm steel 3.48 stroke crankshaft, and a set of dart pro1 215s that I would like to use to build a budget 377 to run in an 83 s10. Engine will be used limited street and at the strip .The block was only ran 7000 miles, so I am almost sure it will clean at .020 and the crank is in good shape,although I will have it rechecked. Assuming the block and crank mag good,would any of you have reservations about using it for this application? Any tips on block prep? Going to use a solid flat tappet cam, so prob be lucky to make much more than 450-475 hp. I was hopeing the shorter stroke would be easier on the mains,and with a .020 over bore and a half fill I will be fine for a season or 2. All the negatives posted about the 4 bolt 400s have me nervous to use it. Also If the crank I have turns out to be no good, would a scat 9000 series hold up in this app? Thank you all very much for your time.

jeff swisher · Post by **jeff swisher** » Mon Sep 22, 2008 8:15 am

Welcome to SpeedTalk...rider8699
I have seen that combo many times in fast street cars, with many different heads and cams , all stayed under 7400 rpm and lived for many years..
The power levels you are shooting for do not seem out of range for that combo,as long as all the machine work is done right.

want-a-be · Post by **want-a-be** » Mon Sep 22, 2008 12:05 pm

rider8699 wrote:The block was only ran 7000 miles, so I am almost sure it will clean at .020 and the crank is in good shape,although I will have it rechecked.
Going to use a solid flat tappet cam, so prob be lucky to make much more than 450-475 hp.

I'd machine the block first then decide on the bore. Go as little as you can get away with. Put a torque plate on the block and have it honed. You might find out it will clean up under .010". You can get pistons in .005" oversizes. I'd take out as little as you can so you can get more use out of your block. jmo....

Don't go to wild on the block filling. On the street you still have to worry about cooling the oil. Fill to much and you lose some of that. But you need to research that and form your own opinion.

Depending on the compression you're targeting...I don't see why you couldn't hit the 500 hp mark. Just do some good home work and don't chintz on the cam selection. Cam Motion or Cam King would be my only choices

That block ought to hold up for quite a while with the hp range you're wanting to operate at. Seen another 200hp live under harsh conditions for quite a while. Make sure you have a quality machine shop do the machining. You get what you pay for there.

Good luck with your build. PM me if you need any help.

Don

WCRE

robert1 · Post by **robert1** » Mon Sep 22, 2008 3:10 pm

I stated in an earlier thread about making the spacers for these. Been making them for about 20 years. I built and maintained a 377 in a 2100 lb Monza that ran a best 5.32 1/8th mile. It lasted several years. Seems like I do remember reblocking it one time for cracks in the mains. In something like your application I see no problem. I am doing a batch of 75 sets right now. So I'm guessing at least 75 more people are going to build one.

bigjoe1 · Post by **bigjoe1** » Mon Sep 22, 2008 6:24 pm

I always tell the kids who ask about doing a 377, that a real 400 will do every thing that the 377 does, and you dont have to rev it up as high, so it will last much longer.. To date, I have built 100 406 size engines, and TWO 377 size engines. If you do not have a cubic inch limit, bigger is ALWAYS better in the long run.

JOE SHERMAN RACING

Todd V. · Post by **Todd V.** » Mon Sep 22, 2008 7:53 pm

For the power your making a 9000 scat crank will be fine. Like Big Joe said go for the cubes and lower RPMs, you and the block will be happier IMO. I would not fill the block to make 500 hp especially if your going to do street driving. As long as the block is in good shape and your cyl walls are thick enough you will be fine. No worries, just put some good bolts in the main caps before it gets line honed.

us7race · Post by **us7race** » Mon Sep 22, 2008 9:57 pm

My uncle runs those heads on his 377.. his is a 509 2-bolt block .030 over.
It has a flat solid lifter cam .558/.549 lift with a Team G intake and a 750 Holley, Compression is 13.5 using a 10cc dome Wiseco Piston.
We used 6" rods in it. It has the Scat crankshaft and Scat I-beam rods with the 7/16" bolts it runs 6.70-6.80 in the 1/8th at 99mph in his S10.
I think you will be fine we shift it at 6500-6600.

rider8699 · Post by **rider8699** » Tue Sep 23, 2008 12:12 am

Thanks for all the replys. I do not have any 400 crankshafts,but if the 350 crank that I have is no good,and I have to buy one anyway,I prob. will do a 400 crankshaft. So looks like I will be safe at 500 or less hp and under 7000 or so max rpm. The engine that is in the truck now is a horrible mismatch of parts. Was told from the guy I bought it off of that it was a 68 327,and the engine block numbers back this up, but I dont know if the stock stroke crank is in the truck,but was told it was. Has 215 pro1 heads,a super victor intake,750 holley d/p,msd dist and 6al box,1 3/4 longtubes,and an unknown solid lifter camshaft(sounds very large-needs to be 1300 rpm or so to idle even halfway decent). Truck has 4.10 gears and a turbo 350 with unknown converter. When I started it the valvetrain sounded horrible, first valve I checked had over .050 clearence

. Checked all the pushrods and adjusted all valves to .018 and amazingly everything looked and sounded good...for now. Friend and I took the truck out on the street, brought it up as high as I could against the converter(2800 on 28 by 10 slicks) and launched it. Truck pulled like a ford escort with 2 plug wires off

till about 4500 rpm when it felt like you reattached them,and then finally at about 5500 we started getting somewhere. Made several runs shifting at 7500 then 7800 just playing with the truck,at which point my common sense told me that the stock rods, cast crank, and old ratty stock harmonic damper prob did not like that. Rockers were noisey again,and upon pulling the valve covers I have a couple needle bearings on the rockers that are done for. Also engine has the highest oil pressure I have ever witnessed,55 to 65 psi at hot idle and jumps to almost 100 as soon as you hit the throttle. Enough of my rambling, thanks again to all who replied.

ProPower engines · Post by **ProPower engines** » Tue Sep 23, 2008 11:10 am

Like Joe said,
the 377 is not all that common but if you are on a budget the pistons will be more$$$ Then pistons for a 400. What you save on the pistons will buy a new crank.

RogerF · Post by **RogerF** » Tue Sep 23, 2008 1:33 pm

The pistons don't have to be more expensive, you can use any stock 400 piston on a 5.7 rod with a 350 crank in this combination. Pin height is 1.560" in either motor.

kirkwoodken · Post by **kirkwoodken** » Tue Sep 23, 2008 1:42 pm

In my opinion, a 377 is a waste of a 400 block. Build a 406, or the minimum overbore you can get by with. Not necessary to go .030" over if you dont have to. Replace the 400 rods with stock 5.7, or go with Scat rotating assy. Good machine work is most important with 400 blocks. They are kind of flimsy. Get your block done by someone who knows what they are doing.

PackardV8 · Post by **PackardV8** » Tue Sep 23, 2008 1:43 pm

Your car, your money, your decision. As Joe says, the extra 29 cubes of a 406" can be worth 30-40 horsepower; just figure how much more it will cost you and make the decision based upon your personal finances. If your 350" crank and rods are sound and ready to go, use them. A strong 377" will pull your S-10 plenty quick. FWIW, Keith Black has a good hypereutectic piston specifically for this application which costs the same as an equivalent 350" or 400" piston. http://kb-silvolite.com/performance.php ... ls&P_id=69

thnx, jack vines

Keith Morganstein · Post by **Keith Morganstein** » Tue Sep 23, 2008 5:09 pm

There is nothing wrong with a GOOD 400 block for that 475-500hp power level. Most don't start to give up until around 600HP and that is in a weekly bracket race application. Problem is that they are getting very old now and there are very few GOOD ones left.

By the time you add the cost of the spacers and checking or grinding the used 350 crank, you might as well just buy a new Scat9000 crank (400 main/stroke). They are $200. for a external balance or internal balance (need 6" rods' for internal)

You have most of the parts already, so it's not like you are sinking large amounts of new money into it.

Good luck with your project.

robert1 · Post by **robert1** » Tue Sep 23, 2008 5:45 pm

Hey you guys lay off the cost of them spacers. I charged the same for the 75 sets I just finished as I did for the first ones I did 20+ years ago. Facts are facts though that's the reason I did 75 sets this month as opposed to 300 sets I used to do in a month. I'm just a flea on an elephants a$$, there are about 4 other people that have made them as well and if I done 25,000 plus sets I'm guessing there had to be at least 150,000 of these things built. Not bad for an engine that's not all that popular. It may not be the best choice but if you've got a block and a crank it's not the worst choice either.

af2 · Post by **af2** » Tue Sep 23, 2008 6:01 pm

Since I run one of those dreaded 377's I have to stay out of this one! I will say Joe is right you have to spin them to get the HP. I shift at 8700 and feel any one making HP should be in that area with a small block. Just my 2!

A 3.48 stroke is less side load as a 3.75 IMO.

Don Terrill’s Speed-Talk

377 sbc opinons please.

377 sbc opinons please.

Re: 377 sbc opinons please.

400 block