434 or 377

[bigdee183]

I cant decide what I want to build for my next motor. Thinking about a 434 because I hear they are torque monsters but I really like to twist my 327 tight thats why I'm thinking about a 377. Who has experience with the 434 or 377? What are the pros and cons? I plan on using nitrous. It will be going in an '89 formula firebird with a th350. It does see some street time but not much.

Thanks
D

[want-a-be]

I'd go with the 400ci if it were mine. You'll be able to see the best of both worlds. But it actually depends on the heads you plan on using.

Don

[supernova]

Well, you could think of it like this: I've seen lots of bracket cars with 377 motors in them, lots of high rpm power not much torque very consistent. Now if your wanting the Saturday night run what you brung and hope you brung enough power I would go with the the bigger cubic inch motor.

Now thats not to say that a 377 can't make good power it can just not what a 434 can make. To give you an example, all the small block cars in the true street class My car is built for have no less than 415 c.i. motors. Most are 421, 434, 454. The bigger c.i. motors just make more power.

You asked and it is just my 2 cents!!!!!

[Hitchcock]

What block are you gonna use?
I greatly agree with supernova on this. Just like the ol lady says, bigger is better!

I built a 496, and wish I spent the money on an aftermarket block for a 555 or a 572!

[want-a-be]

What block are you gonna use?
I greatly agree with supernova on this. Just like the ol lady says, bigger is better!

I built a 496, and wish I spent the money on an aftermarket block for a 555 or a 572!

I agree with you guys on this. Especially when building with the BBC heads that available today. But going with the Small Block...it greatly depends on the heads as to how much RPMs he will be able to make power at with the larger ci. If he wants to stay under 6500...maybe even 7000,...then sure go with the larger ci. But if he wants to hit 8k or so,...and make power there then he is going to need the head to support it,.. or go with the smaller inch. Thats why I say 400 inch is a good range...enough for stout bottom end and also be able to make hp in the upper RPMs.

If you're wanting a very strong street combination I can turn you onto a guy who will be more then happy to share what he has in his street car. Driven on the Hot Rod Mags Power tour this year. Made something like 625 hp with the 400.

Go to http://www.dartheads.com/dartboard/index.php and ask for Jake...he will answer right off.

Don

[mytmouz]

My previous engine was a 377, LUV'd it, The 428 I have now is quicker, which is why I sold the 377 after trying this one. No need to go backwards...

[bigdee183]

Thanks for the info. I found this on another forum and was kinda leaning toward the 434.

"Take a 2-bolt SBC (high nickel) block. Buy 5, not 3, billet splayed mains . Spend $ 1200 having it line bored, decked and new cam bearings installed along with a .040 torque plate bore job. Buy an Eagle rotating assembly and here's the catch 6 inch h-beam rods already clearenced so you don't have to run a small base circle cam, along with a 4.00 stroke forged crank and you have a 434. Then to run on pump gas a set of Mahle 10.4 compression pistons ( with 64 cc heads ).Then add a set of Dart 227 100 % cnc heads ($2200). Add a good intake and carb and you got 600 very streetable HP. You can do it with a Dart block, just add another 1000 bucks to the price. If I was building a full race motor, yes a Dart Block, but a stout street motor This splayed main block is beat. Wayne
434 SBC. 400 block, splayed billet mains, Eagle rotating assembly. Mahle 10.4 pistons Comp solid roller 255 @ 50 with 575 lift. Dart cnc heads 227, hurricane intake Holley satin finish 850 DP. Motor should make over 600 hp."

I dont plan on racing it every weekend. We just go once and a while to a tnt or a run what ya brung race so I dont really want to spend the money for an aftermarket block when I have a 400 in the shop. I have a good set of aluminum heads that flowed 261.4cfm @ .600 (not sure what brand) but I think this combo would make a pretty stout street/strip motor.

[jmarkaudio]

If you go the 434 route I would highly suggest using a 2" rod journal. Don't let anyone try to tell you it will be too weak, Pro Stock runs Honda 1.88 rods and 283 mains at 500 inches. Your clearance issues will be minimal with a 2" rod, the large journal has issues not only with the block, but also the cam. Having built a 4" stroke 427, a 4 1/8" stroke 447 in a raised cam Iron Eagle, and currently a 4.25" stroke 461 in a 9.5" deck, raised cam aluminum block, I have seen what the problems are that can arise.

As far as a block, with what you plan to spend you would be far better off with a Dart SHP block and not spend much more. A factory block can be made to work, but quality castings are hard to find and are a gamble for the HP you are talking about as to whether they will hold out in the long run. If it were me on a budget, I would opt for some as cast Dart heads taking the savings and putting it toward the block. Better to have a solid base short block that will take anything.

[supernova]

Thanks for the info. I found this on another forum and was kinda leaning toward the 434.

"Take a 2-bolt SBC (high nickel) block. Buy 5, not 3, billet splayed mains . Spend $ 1200 having it line bored, decked and new cam bearings installed along with a .040 torque plate bore job. Buy an Eagle rotating assembly and here's the catch 6 inch h-beam rods already clearenced so you don't have to run a small base circle cam, along with a 4.00 stroke forged crank and you have a 434. Then to run on pump gas a set of Mahle 10.4 compression pistons ( with 64 cc heads ).Then add a set of Dart 227 100 % cnc heads ($2200). Add a good intake and carb and you got 600 very streetable HP. You can do it with a Dart block, just add another 1000 bucks to the price. If I was building a full race motor, yes a Dart Block, but a stout street motor This splayed main block is beat. Wayne
434 SBC. 400 block, splayed billet mains, Eagle rotating assembly. Mahle 10.4 pistons Comp solid roller 255 @ 50 with 575 lift. Dart cnc heads 227, hurricane intake Holley satin finish 850 DP. Motor should make over 600 hp."

I dont plan on racing it every weekend. We just go once and a while to a tnt or a run what ya brung race so I dont really want to spend the money for an aftermarket block when I have a 400 in the shop. I have a good set of aluminum heads that flowed 261.4cfm @ .600 (not sure what brand) but I think this combo would make a pretty stout street/strip motor.

Now that sounds like the ticket!!!! I ran stroked sb's for yrs. Well what happened next was a friend let my drive his big block extreme 10.5 car and that was all she wrote. It's nothing but BB's for now on!!!!!!!!!

[dakster]

Remember the old saying: "There is no replacement for cubic inches" If you are looking at making 1.5 horsepower per cubic inch, the difference is 85 horsepower just upgrading from the 377 to the 434.

[want-a-be]

What heads are you actually going to run? What RPM are you wanting to twist this thing to?

Don

[soslojoe1970]

I have ran several 434 motors and turned them 7500rpms. End or year took it apart and all the cylinder were out of round, piston skirts all ate up from the side thrust and alot of main caps walking ( on a good splayed block). I now have a good flowing head 400 inches and 8600rpms making much more power. Now taking it apart and still see hash marks on the cylinder walls.... nice.

[Bowtiestang]

Remember the old saying: "There is no replacement for cubic inches" If you are looking at making 1.5 horsepower per cubic inch, the difference is 85 horsepower just upgrading from the 377 to the 434.

Thats an OLD SCHOOL saying...the replacement is boost