Here's the scoup,the 400 rod is a cheaper rout and makes SLIGHTLY more torque down low.Now the 350 rod makes more peak HP and SLIGHTLY less torque down low.

The main considerationhere is that the 5.565 rod puts more side loading on the cylinder walls than the 5.7.

More side loading = More friction.

More friction = A finished bore size that won't last as long.



[This message has been edited by mutant 68 (edited 12-28-2000).]

 

Eric,

Mutants right. GM knew when they designed the 400 that it wouldn't last as long in the cylinderwall department as the other small blocks because of the shorter rod creating more load on the walls, but they probably figured whose gonna wrap a two barrel engine thats in a Caprice up anyway.

Usually you have to check the middle to rear cylinders for wear moreso then the front to middle cylinders, I think.

Plus, putting the 350 rods in it make it a mute point anyway. pdq67

 

Be carefull when putting the 5.7 rods in with the 400 crank. The rod bolts will usualy hit the cam! Check each rod CAREFULLY when doing your trial assymbly. All you have to do is lightly grind the head of the rod bolts that hit to get about .060 clearance to be safe. The 400 rods have shorter bolts.

------------------
'69 RS/SS396 pro street
427/4spd/9"

 

Big gear is right. Pay particular attention to rods numbered 1, 2, 5 and 6 per John Lingenfelter. pdq67

 

5.7 rods will have a lower accelleration, less side loading, lower peak speed as well, which makes your bottom end safer for a few more revs, as well as more efficient and longer lasting. Consider 6" rods, it might not cost much more (Eagle SIR rods, KB pistons).

Rob

 

Thanks guys - sounds like 5.7 or 6" is the way to go. Any block relieving or special mods to use the 6.0" rod? That seems like an awefull long rod to squeeze into a 3.75 stroke small block - must have relocated the piston ring lands for the higher wrist pin placement. I'll check out the prices. BTW who is a good source for the Eagle rods and crank? I've heard others speak well of the Eagle pieces, but haven't seen much of them in the catalogs. Spotted the rods in JEGS. Haven't seen any Eagle stuff in PAW or Summit.

Maybe I can get that Lingenfelter guy to build one for me . . . if I hit the Lotto.

 

You can find Eagle rotating assemblies at Xtreme Racing.
www.nexternal.com/xtremeeng/

 

There is one more thing to think about when choosing between rod lengths,that's compression ratio.

As the rod gets longer your choice of pistons with a streetable compression ratio dwindels.

[This message has been edited by mutant 68 (edited 12-29-2000).]

 

I had a 400 with the short rods and it made a lot of piston noise.

I later rebuilt it as a 383 (long story) and used the 5.7 rods ground on the bolt heads.

It's working well and MUCH quieter.

If it's a budget engine do the 5.7's

I have a set of the Eagle "ESP" H beam rods and they are nice.
They have an "SIR" I beam rod too made in 5140 steel 50% stronger than stock.

They have some very nice people on the phone too.

E-Mail at eaglerod@netten.net


------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

 

Oops!

[This message has been edited by davidpozzi (edited 12-29-2000).]

 

Thanks guys. jgreen - liked the xtreme racing site. Think I found my rotating assembly there. 9.7:1 Keith Black's, Eagle 5.7 SIR's and the new cast crank. Now I need a block - looking at the new GM bare block part number 10066034 but can't find out much info other than it's 4 bolt, 4.000 unfinished bore and "bare." Rated by GM to 350 HP at 5750 - that concerns me a little bit, was shooting for an honest 400 HP and 6,000 R's. What do you think? It's a big jump in price to the bowtie block.

Hmmmm . . . I could always save the $'s by flipping my kid's diapers inside out before changing . . .

Happy New Years! Have a safe one.

 

Eric,

You might want to check into the new Motown block that is from Merlin. I read an article about it and it sounded like a good block for a stroker small block. The article was either in CHP or Super Chevy. My daughter tears them up pretty fast, so I don't know which one it was in.

Kent

 

Kent,
It was in both magazines.

I would find a seasoned (used) block and have the machine work done to it (much more cost effective). If you can afford a new GM block or a MOTOWN block why not call BECK RACING ENGINES (beckracingengines.com) and get a complete motor, dynoed and all for that kinda money.

------------------
TONY
67 CAMARO R/S CLONE, 355/turbo 350, 200hp NOS,12 bolt,etc...

 

I donno, that Merlin block punched out to 4.25" and stroked to 3.875 just really turns me on at 440". But hey, with a standard bore of 4.20" and a 3.25" gives 360", a 3.48" gives 386" and a 3.75 gives 416" so any of the three strokes would be fine.

Add a set of them mini-big block heads and hold on. He, He!! pdq67

 

Man that would be AWESOME with some splayed valve heads!!!WAY

[This message has been edited by mutant 68 (edited 12-30-2000).]

 

The new GM block goes for about $600 - I figured machine work on a used block would would add up pretty quick so it's nearly a wash there. I'll look up that Merlin Motown block - that could be a good option if the price is right.

Hmmm 4-1/4 bore, the extra cubes could be worth it. Haven't seen any splayed valve heads though - thought that was a big block thang.

 

Splayed valve heads for small block is,as they say,MUCHO DENARO

[This message has been edited by mutant 68 (edited 12-31-2000).]

 

No hablos "Mucho Denaro." Might try some 23 degree Trick Flows or Sportsman II's though.

 

Eric,

I gotta feeling that the Motown block is $16/$1700 plus truck freight. And a set of them mini big block heads, no telling, maybe $3/3500??? complete. Any NASCAR guys out there???
Then add the intake and headers, WOW!!!

Very pricy, but you would have a mini-rat. And the heads intake cc is about 260+, just about Merlin oval port size, so the sucker CAN breathe.

I gotta win the Lotto!! pdq67

 

You can check out the Dart and World Products blocks in the Blocks & Accessories section at www.flatlanderracing.com

The World Products Motown block is $1549 while the Dart Iron Eagle block is $1799. I would love to have one of these blocks for my next engine also, but just can't justify the price. I have read where it may actually be preferable to go with the older block and have it machined. The thought here is that it has gone through the heating and cooling cycles so many times that all the core shift that can occur has already taken place. This may be a case of splitting hairs though.

 

Eric - the $600 for that block is deceiving - you'll need just as much machine work on it as you would on a used block; just not the cleanup (but that's cheap). Find a 350 block, build a 355 - 2 bolt mains can handle more than 400 hp & 6000 rpm. For some added security, stud the mains, that won't cost too much and should be more than adequate for your needs.

Seasoned blocks are preferable to unused blocks anyhow, the cycling of heat makes the metal 'settle' - with a new block, it still may warp or deform after it's gone through the hot and cold cycles quite a few times. That's what David Vizard says anyways; I'm no metallurgist, but he seems to know his motors.

Then take that extra cash and get some aluminum heads! The $850 Twisted Wedge seems to be a good deal, but I'd spring for the $1100 Canfields, or the $1200 AFR's personally. Then get some Rhoads lifters & a 230/236 or so hyd flat cam, a Performer RPM or equivalent, and you'll be well over your 400 hp @ 6000 goal.

Rob

 

You guys are "unmaking up my mind" pretty darn quick. No pun intended PDQ67. I'm sticking with the 383/5.7" combo with the Eagle reciprocating ***'y, but am thinking I have more options with the block.

I might have to stomp around the ole boneyard to see what kind of a block I might scroung up. Maybe I can find a good 2 bolt core and add the Milodon splayed caps on the center three mains. (Already doing the machine work anyway - right). I don't know why GM would only rate their new blocks to 350HP when word on the street is that an old 2 bolt block can handle 400!? Maybe somethin to do with that core shift thing.

As for heads and cam - well, it gets mudier. I'll have to wait for my copy of Desktop Dyno to arrive. Happy New Years may your asprin work fast.

 

Right on, Eric.

The General is way conservative with the strengths of their blocks that are really hammered on for a short time. (Like a 1/4 mile blast)

If I was building a boat engine or an over-the-road truck engine then I would be more conservative too.

Stud the 2 bolt mains for the extra peace of mind. Drop in your crank, torque the caps in place and spin the crank. If it spins you probably don't need any main jounal machining. IMHO. pdq67

 

What kind of HP are you looking to produce?

[This message has been edited by mutant 68 (edited 01-01-2001).]

 

The goal is 400 horsepower below 6000 RPM. The lower I can move the power band the better for the street. I would also like the engine to idle reasonably well and be reliable in traffic - not prone to overheating and stalling. That is the main reason I chose the 383 with 5.7" rod combo. At that displacement with the right combo of parts I believe I can do it.