I know these threads are repetitive, but spring is near and I still have not run my car on the road. I have a 355 small block 10.6:1 compression ratio +/-, 4 bolt main w/ forged Weisco (sp) pistons, stage II connecting rods, ground stock crankshaft for the shortblock. I have Dart Iron Eagle 215cc/64cc cylinder heads. Clevite 246/246 @ .050, .498/.498 INT/EXT solid lifter camshaft. Scorpion 1.6 roller rockers, performer RPM intake manifold and a freshly rebuilt Holley 650 DP. All backed by a T-56 Transmission to 3.73 Richmond gears and a Zexel posi unit. Could somebody give me an educated guess on how this car will do HP/TQ wise, or quarter mile wise roughly? The only suspension mods I have are Spohn SFC's and Lakewood lower control arms. It's been under construction for over 2 years now and I get to take it out this spring.

Any help would be appreciated.

Zach

 

Anybody?

 

I'd guess 425 ft-lbs @ 4800 and 425 HP @ 5600, and crater after that. Real steep torque curve, with a big peak, basically nothing below about 3500. Maybe 12.7@106, trap in 3rd gear.

It's kind of significantly mismatched. You've got CAVERNS for intake ports, but a little weenie lazy el cheeeepo copy of an obsolete factory cam that barely even cracks the valves open. That cam is leaving probably 50-75 HP on the table.

The carb is also too small.

What it will do, is have a real soft leave, with that tall stock highway gear; it'll build up a pretty good head of steam near the top of the gears; and then just suddenly run out like it hit a brick wall. It'll be easy on parts though, because that cam will barely even disturb the valves, let alone aggravate them.

It needs either MUCH smaller heads, or a MUCH larger cam; and a 750 carb. And some gear. Fix those things, and you'll also be needing some LCA reloc brackets.

 

Sofakingdom,

The car has 3.73 gears, not 2.73 gears that you are thinking of.

 

as is, i would say high 12's.. like sofakingdom said, cam it, carb it and smaller heads.. something around 195cc.. those dart 215's would go nicely on my motor(11.2:1 385).. you should also look into some 4.10 gears.. especially with the t-56.. that will get you trapping in the correct rpm range..

on second thought, that cam will work pretty good.. but those heads are way too big.. i'm betting the cam rpm range is around 2500-6500ish..

 

Right... 3.73.

The stock gears in a couple of my cars, including my thirdgen, which has a 305 and a T-56. With that transmission, those are highway gears.

It's just not enough gear. Just like it wasn't in all those late 60s muscle cars with 4-speeds with about the same 1st gear ratio that the T-56 has. We all used to jerk the stock gears out and put 4.11s or 4.56s in them. 11s for big blocks, 56s for small blocks.

It's especially not enough gear for a little motor, a small block at that, with too much heads. It's bad enough for a big block with square-port heads.

I think you'd do ALOT better with less heads and a better cam, if you stay with those gears; or a bigger carb and a better cam if you fix the gearing. Either way, that cam needs to go. It's almost 40 years old now. We've learned a thing or 2 as a species since then about how to make them run good; let alone the change in conditions, expectations, and competition over the nearly half-century since it was introduced.

 

I know I have a dino cam in there right now. I'm working with what I had. I'm planning on keeping the heads and eventually upgrading the camshaft. What would some of you guys recommend for a cam for my set up? How much better would my combo be with your cam of choice?

Zach

 

I would suggest either this one or this one. Either one will run rings around that old cam. Like I said, probably something in the 50 HP neighborhood of difference; a little less with the first one, a little more with the 2nd one. 1.6 rockers will make a significant difference with either one, but be aware, the lift will be over .550". Make sure the valve spring package on your heads is set up adequately.

You could get closer to a 75 HP advantage by going to a solid roller; but that's a pretty big leap of whatever, from an archaic stock cam.

I was wrong BTW... that old factory one is OVER 40 years old. I was giving it credit for being new in the 302, but it wasn't. After thinking about it for a while, I recall that it was first used in 327s in about 64 or 65. Great cam for its day, but LONG SINCE surpassed.

And of course, SOME GEAR. Those stock 3.73 gears gotta go.

 

Thanks sofakingdom, with either of the two cams you recommended, can I still use the solid lifters I have in my car? I only broke in the cam and that was it. Man, I want to drive this car, but the salt on the roads and my exhaust trouble wont allow it.

 

Technically, yes.

However, as far as the mfr warranty on any of it, you'd have to take that up with the mfrs. Which is a BIG deal in this day and time, with all the oil-related problems that are affecting flat-tappet cams. Personally I rather doubt that they would honor any kind of warranty, but I'm no expert and certainly what I say carries no weight with the mfrs.

 

Ok, the machinist at the machine shop that built my motor said I should be at a mid to low 12 second car @ 110 to 113, he also said the car should pull pretty steadily to 6300-6500 rpm. He is a VERY respectable builder in my area and builds motors for plenty of guys in pro street at our local track. I'm kind of tapped on the cash situation looking at a house and all, but I hope with some sticky tires and a good 60 ft. i can pull a mid to low 12 out of it, being well tuned of course.

Zach

 

Are the Dart Iron Eagle heads bolt ons out of the box or have they been worked over some?

 

They have been worked over a little bit, minor porting, larger valves, and some other things I'm not quite aware of.

 

now that i look it over, it seems like a really nice combo.. IMO, the heads are a bit overkill for a mid 12 second 355.. but it should def. get you the mid-low 12's you are looking for.. and for the gearing, i suggested 4.10's so you can trap in a higher RPM, closer to peak.. with a 26" tire, at 110mph, i trap around 5600 with a 3.89 gear.. you will be trapping at about 5500.. but the 3.73's will work fine other than that..

with my first motor, i had low 12-high 11 potential with a 10.7:1 383 with ported camel backs(1.94/1.50 valves), performer EPS manifold, similar cam as you(.525" 248* @.050"), and an 800 edelbrock carb.. motor took 3 runs on slicks before it threw a rod from oil problems.. but it pulled off a 12.7 @ 107 first time out with the slicks.. missing fourth gear as well.. and a horrible 1.8 60ft.. had i gotten the 60ft down to 1.6xx, and banged all my gears good, i would have had an 11 second car..

 

Sounds like a quality build. Hard to judge but I will go along with the above posters. The 215cc heads will want to wind high.

You will need a cam to go with them. Maybe what Sofakingdom suggested. I would get the dynamic compression ratio up as high as you dare because of the 215cc heads. That will help with the VE.

 

Thanks for the replies guys. I am going to try to optimize this combo and see if I can either break the 11.99 barrier or break my rear axle. I hope I can see a 12.00 out of this after I've tuned the heel out of it.

Zach

 

if it doesnt hit faster then a mid 12, spray the crap outta it.. just kidding.. hope you can bang gears.. good luck..