4" stroke 350

[novaman408]

Does anyone have any experience with a 4" stroke 350? 400 blocks getting scarce nowadays, I've been entertaining filling a 350 and trying one, I've seen a few ads for them lately. I'm sure the block will need considerable clearancing, what about cam clearance? Some of you guys with some good experience should chime in here. I know the Dart block would handle no problem but i'm trying to stay with what i have so lets try to focus on the factory block this time.

[billhendren]

Crank to cam centerline is the same as a 400 block.with the 4.00 stroke you should at least install splayed main caps unless you have 2482 nodular iron main caps on the block already,the 3412 gray iron caps will fail with a stroke that long.Bill

[novaman408]

Is there enough material in the block when using the aftermarket mains it's not too weak? I'm thinking about a .030 with a 4" stroke for a 408(I believe) currently running a 383 with 6" rod, 13.5 comp, lunati 618 roller and 215 RHS heads and really like the combination. Runs 6.50's in the 1/8 in 2600lb car, I feel like a few more cubes would help and i have a spare 350 block in the garage just waiting for a build, and that would be worth about 20ci and be an interesting combo to put together. I dont really hear too much about them and was worried there might be a reason. Thanks for the input,

[ImBack]

Is there enough material in the block when using the aftermarket mains it's not too weak? I'm thinking about a .030 with a 4" stroke for a 408(I believe) currently running a 383 with 6" rod, 13.5 comp, lunati 618 roller and 215 RHS heads and really like the combination. Runs 6.50's in the 1/8 in 2600lb car, I feel like a few more cubes would help and i have a spare 350 block in the garage just waiting for a build, and that would be worth about 20ci and be an interesting combo to put together. I dont really hear too much about them and was worried there might be a reason. Thanks for the input, Maybe a head change?My 6" rod 383,13.5 comp.,dart 215 iron eagle platinums,with a Howards 555 lift flattappet cam on alky made 586 hp. at 6600,510tq. at 5000 and went a 6.36 best in my 2800# malibu.I think your cam is too much for those heads??

[novaman408]

It could very well be too much cam, I'm putting it on alky (toilet) this year, I've already got it changed over and ready to see how it reacts to the different fuel system. I've actually been pretty pleased with it so far, I've just been thinking about a different short block. On a side note, before the RHS heads I was running Victor Jr's and it was running 6.80 best case, when i changed to the RHS it literally dropped .25 which I thought was pretty impressive. The only difference in the heads was the cc's, Victors=70 RHS=64cc, i'm not sure how much this affected the comp ratio but it sure did make a difference in performance. Both heads were straight out of the box and the only change was the heads themselves. I never really considered a cam change, but it might be what is holding back the 60' numbers (usually 1.41-1.42) and a smaller cam might put a little more bottom end into it. I guess the reason I ran it was I got it dirt cheap.

[fishman1]

Is there enough material in the block when using the aftermarket mains it's not too weak? I'm thinking about a .030 with a 4" stroke for a 408(I believe) currently running a 383 with 6" rod, 13.5 comp, lunati 618 roller and 215 RHS heads and really like the combination. Runs 6.50's in the 1/8 in 2600lb car, I feel like a few more cubes would help and i have a spare 350 block in the garage just waiting for a build, and that would be worth about 20ci and be an interesting combo to put together. I dont really hear too much about them and was worried there might be a reason. Thanks for the input, Maybe a head change?My 6" rod 383,13.5 comp.,dart 215 iron eagle platinums,with a Howards 555 lift flattappet cam on alky made 586 hp. at 6600,510tq. at 5000 and went a 6.36 best in my 2800# malibu.I think your cam is too much for those heads??

I am running(last year) a 383 ..6 inch rod .. 13.4 cr ..634 lift 272 duration roller ..hurricane intake..850 carb...1 3/4 headers...victor jr 215 heads 64cc in 2400 lb car @2300 feet made 565 hp...cam wasn't a issue for me the heads and intake were...this year i changed the block to a dart and changed the heads to afr 210 competetion heads opened up and a super victor intake that was ported by a exelcellent porter with a 950 carb and ceramic coated the headers hoping for 630-650 hp on the dyno

[novaman408]

So anyone else have any input on the 350 block/4" stroke combo?

[edvancedengines]

I advise strongly against the 4 inch stroke in a stock cam ht 350 block.

If you are an experienced stroker engine builder and fully understand what to do and where and why to end up with the correct clearances and not grind into water or oil passages, you will have a lengthy time consuming chore on your hands.

If you aren't you are in for a learning experience which can eat up several days time and that is if you don't ruin the block while cutting.

Ed

[mytmouz]

Did this with a stock 010 block and a Eagle crank, 6 inch I beam rods and a small base circle cam. Block filled the lower part of the water jackets and it went pretty well. Only had to clearance some on the pan rails. This was swap meet stuff a friend of mine and I experimented with. The guy we got the stuff from said it was a common circle track 'equalizer' combo.

[novaman408]

I was thinking of enough fill to get me out of any water jacket issues when i start clearancing and figured that i would have to take out some from the pan rail. Is the small base circle cam a necessity? How did it perfom in comparison to some other combos"

[mytmouz]

We used the small base circle, since it was already on hand. Whether you need to or not will depend on the rods you use, IMO. The motor runs good, it's still in use. It ran mid 10's in a fairly heavy vehicle on motor only.

[zipper06]

I was thinking of enough fill to get me out of any water jacket issues when i start clearancing and figured that i would have to take out some from the pan rail. Is the small base circle cam a necessity? How did it perfom in comparison to some other combos"

Unless you already have the 4" stroke crank, i would go to 3.875. This way you can use a conventional grind cam. I personally have a 434" dart blk. with Lunatti promod rods and bullit ground me a .875 base circle 4/7 cam for the motor, it's a .688/.668 lift and i plan to use 1.6 rockers. But to answer your question more directly, yes you have to use a small base circle cam, .900 or less even with "H" beam rods with a 400 blk or a 350 blk.
Between my friend and i we have (5) 434" motors and (3) with dart blks. and 2 with 400 blks. all have spladed caps and all have small base circle cams and all run on alcohol.
Now the combo i mentioned above 3.875 crank. I have a friend living a few miles away that will only run 350 blks. with 3.875 ultra light cranks an alum rods with light weight pistons. He runs 394's with 2" crank pins and 420Gm pistons on an alcohol toilet bowl, in a shoebox 55 chevy weighing 2650lbs. with driver. It will run 9.20's all day long at 142mph at twin cities,La.
It hurts lots of B/BLK people to hear this but it's a fact. i'm getting ready to put my 434" into my 3250lb Malibu and fully expect it to dip deep into the 9's @ over 140mph, estimating 5.80's or better in the 1/8 mi.
One of the 434" stock blk. motors i mentioned runs 4.80's in a dragsters and has over 200 passes on it.

JMO

Zip.