[A.W.Dille]

With the 4.88 gear you may be turning 6700 through the traps. I'd make sure to have forged rods. The 041 likes rpm and should pull to 6500 or so with no problem.

[ponchonlefty]

Originally Posted by A.W.Dille

With the 4.88 gear you may be turning 6700 through the traps. I'd make sure to have forged rods. The 041 likes rpm and should pull to 6500 or so with no problem.

i agree . i dont really know about converter slippage. so what ya think 4340 or 5140 rods? i would like to use the stock rods not because im cheap but i would like to see how far i could push them. but forged rods are definitely going to be used. guy gave me a 400 engine with a firebird i bought for parts i took the pan off it had 4 broken rods in it. i have never seen that many broken rods in a block and not have a hole some where before, but there it was. i bet that was a heck of a sound. thanks for the input.

[Formulajones]

Friend of mine had a 62 Catalina with 4.88's. He ran a mild 389 in the car, single 4 barrel, with a T-10 4 speed behind it. He ran 30" tall slicks on the car.

The engine wasn't a power house but the combination worked well enough and looked like a hoot to drive. Just something fun that wasn't hard on parts.

It would run high 13's at about 105 mph. It was only running through the traps around 5800, so the 4.88's weren't as big a deal as people make it out to be. In fact, it was about perfect for the setup he was using. I have some old VHS footage of it around here somewhere.

So technically speaking, if the 400 is built to make peak HP up around 5500-5700, and you keep the 30" tire, the combo can be made to work well with the 4.88's. The key with the automatic would be to get a converter in there that flashes where you want but couples well enough on the other end.

[ponchonlefty]

Originally Posted by Formulajones

Friend of mine had a 62 Catalina with 4.88's. He ran a mild 389 in the car, single 4 barrel, with a T-10 4 speed behind it. He ran 30" tall slicks on the car.

The engine wasn't a power house but the combination worked well enough and looked like a hoot to drive. Just something fun that wasn't hard on parts.

It would run high 13's at about 105 mph. It was only running through the traps around 5800, so the 4.88's weren't as big a deal as people make it out to be. In fact, it was about perfect for the setup he was using. I have some old VHS footage of it around here somewhere.

So technically speaking, if the 400 is built to make peak HP up around 5500-5700, and you keep the 30" tire, the combo can be made to work well with the 4.88's. The key with the automatic would be to get a converter in there that flashes where you want but couples well enough on the other end.

thanks , thats what i was thinking. thought i would start there then make changes like intake, cam. no hot rod is ever done.

[433lemans]

Originally Posted by Keith Seymore

That's a lot of opinions.

K

Lol! It is! I got it.

[Half-Inch Stud]

Toss the 4.88s in the creek, and Run it on the Converter. 4340 rods, then 5140, instead of cast.

[Formulajones]

Sometimes you just gotta lick your eyebrows and be somebody

[Skip Fix]

My 400 would go 6500-7000 depending on the cam but had good rods.12 teens @112

[ponchonlefty]

Originally Posted by Formulajones

Sometimes you just gotta lick your eyebrows and be somebody

lol yeah fortune favors the bold but sometimes when you let them hang theyre hanging out of the block. heh heh thats racing i guess.

[Formulajones]

Originally Posted by ponchonlefty

lol yeah fortune favors the bold but sometimes when you let them hang theyre hanging out of the block. heh heh thats racing i guess.

That was something that a group of car guys we all hung around would say to each other, so somewhat of an inside joke. Good times.

[ponchonlefty]

Originally Posted by Skip Fix

My 400 would go 6500-7000 depending on the cam but had good rods.12 teens @112

there is no question rods would be a good investment. are we having fun yet?

[ponchonlefty]

Originally Posted by Formulajones

That was something that a group of car guys we all hung around would say to each other, so somewhat of an inside joke. Good times.

sounds like my kind of people.

[Formulajones]

These days I'd invest in rods even if it were a 5500 rpm engine, it's just not cost effective to work over the stock 50 year old stuff anyway.

But 4.88's with a 30" tire behind a mild 400 that might make all of 400hp isn't going through the traps at 7000 rpm either.

[Formulajones]

Originally Posted by ponchonlefty

sounds like my kind of people.

They are a good bunch, that just like cars and racing.

[lust4speed]

Wallace calculator says that ignoring converter slip the 30" tire, T400 trans, and 4.88's is going to give you 109 MPH at 6,000. Factor in normal slip and you are probably at 105 MPH at 6,000.

[ponchonlefty]

Originally Posted by lust4speed

Wallace calculator says that ignoring converter slip the 30" tire, T400 trans, and 4.88's is going to give you 109 MPH at 6,000. Factor in normal slip and you are probably at 105 MPH at 6,000.

yeah thats the calculator i was using. thought hmmm it could be a fun hot rod.thanks for the response.

[ponchonlefty]

Originally Posted by Formulajones

These days I'd invest in rods even if it were a 5500 rpm engine, it's just not cost effective to work over the stock 50 year old stuff anyway.

But 4.88's with a 30" tire behind a mild 400 that might make all of 400hp isn't going through the traps at 7000 rpm either.

i agree , now we got some wheels turning. this is why i came here.cool people to bounce ideas with.

[ponchonlefty]

Originally Posted by Half-Inch Stud

Toss the 4.88s in the creek, and Run it on the Converter. 4340 rods, then 5140, instead of cast.

what stall? what gear? thanks for the response . every suggestion is duelly noted.

[krisr]

Originally Posted by ponchonlefty

that sounds like a good combo. what kind of car?

1971 Holden HQ Monaro. Basically the Australian version of a 1970 GTO but a few hundred lbs lighter.

My 400 with my driveline combination will pull 11.4 @ 120mph in full street trim with a set of 295/55 drag radials on. The solid roller is the key for my heads/induction. 1-2 shift is at 7200rpm. 2-3 is about 6900. Across the line at 6800. I got the mph there to go quicker, but it’s a fat heavy pig so it won’t 60foot without help (transbrake or nitrous).


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[Formulajones]

Originally Posted by lust4speed

Wallace calculator says that ignoring converter slip the 30" tire, T400 trans, and 4.88's is going to give you 109 MPH at 6,000. Factor in normal slip and you are probably at 105 MPH at 6,000.

Yep, so unless you have a pretty rowdy 400 making some steam, I don't see it going more mph than that in a typical weight street type car.

Even 7000 rpm will get you up around 127-128 mph with that gear and tire combo, maybe 125-ish with a good converter that isn't complete mush.

That's the key with an automatic, getting a converter built that flashes well enough with that gear, but still couples decent at the top of the track without too much slippage.