Ok guys, getting ready to start a new engine build and looking for some sage advice. So I guess we'll start with goals.

1. Must look roughly stock
This means the engine must be N/A and must have drool tubes. But I'm not opposed to improvements that can't be seen (larger valves, overboring or stroking) or might be overlooked (super mini starter, HEI, etc).

2. Must be reasonably streetable
The car is no longer a daily driver so it doesn't necessarily have to be very well behaved. But it will only see one or two dragstrips a year, so I don't need an all out race car.

3. I'm hoping for close to 250hp
I realize this might not be possible with my self-imposed limits, but gotta start somewhere. I want to avoid as much horsepower envy as possible when around my friends with SB V8s. If 250hp is unreasonable given the other goals, help me pick something a bit more achievable.


There are a few parts I've got sitting around that I'd really like to use, but am willing to consider other options if the potential yield is great enough. I have a set of engnbldr 1.7/1.44 valves, springs, and locks. I' also have a Super Six intake and Holley 2280 that I'd like to use. I'm not exactly sure what the CFM rating for the 2280 is but my guess is that it is very similar to the Carter BBD and flows around 280 CFM (anyone have the correct figure?). How can I figure out the max hp that is supported by a carb?

My initial thought on selecting an engine block was to either use a cast crank block for its lightness but if that doesn't pan out I'm fine using my block since it has the right casting numbers. Can anyone comment on how much benefit I would see from the slight decrease in rotational mass and frictional losses? For rods and pistons, I thought I'd go with a long rod setup via the K1(or Molnar)/Wiseco combo, probably a little overbore. I've also thought about the possibility of offset grinding the crank but it sounds expensive and I'm not sure how well that would work with the long 7.005" rods. Not sure what will happen with the head yet since I don't even have a block selected but the basic plan is the larger valves (1.70" intake, 1.44" exhaust) with some mild porting. Once the long rods are in, if I have enough room to mill the head and/or block which should I go for?

I suppose I should also mention a budget, I've got $3,000 allocated for both engine and exhaust work but might be able to add a little more if it'll make a big enough difference.


Now that I've explained my plans, do they seem solid? How likely am I to achieve my goals with the plans discussed so far? And most importantly, is my budget lacking for the work I have planned?

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'66 Dodge Dart

What transmission?

With automatics, you need to think more torque, less rpm than you can get away with a manual.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

At 250 NA you have a lot more thinking to do...

A BBD, mild porting, O/S valves, and a mild cam with a bump in compression, mild porting, and a small over bore will yield about 150-160 hp and a fair amount of torque for street...you will get good gas mileage....lookin' at about a 17 second 1/4 mile...the V-8 guys will weigh in about 2 seconds faster for the slowest entry.

Going to a cast crank block will allow the engine to rev up quicker, but you will only notice when you shift gears and are on the go pedal. (My last cast crank build with the Holley 2305 and 9.66:1 SCR, weighed in around the 170 hp range but used stock valves).

Molnar pistons and rods are going to require a fair sized overbore to install...once you go this route...the engine will want to breathe more to use the volumetric efficiency better with more compression, so more porting, bigger cam, O/S valves, and much more carburator.

To get what you want for #3, you are going with more compression, bigger cam, 4 barrel, stall convertor, 3.xx rear gearing, O/S valves, lots of porting, better exhaust... it will still be streetable, but you won't be able to hide the engine as "stock" looking with the required add ons.

You can easily get 190 out of this combination and it is very streetable:

10:1 SCR
Erson 270 cam (go 280/270 if you want a little "lump" in your idle).
1.70/1.44 valves + porting
Small 4 barrel
Dutra Duals
Stall convertor
DCR in the 8:1+ range...

Are you assembling the long block or is the machinist?

emsvitil, yes it is an auto (904). I hadn't considered this, glad you chimed in.

DusterIdiot, I figured if the hyperpak put out 195hp with standard bore, stroke and valves I should be able to get similar performance with more bore, stroke and valves. If that logic is completely wrong I'm happy to put it behind me and accept a more reasonable hp goal.

As for carb selection, if I were to build the engine with a 4bbl in mind but swap on a super six setup for car shows, would the car still be drivable with the 2bbl or am I asking for trouble?

I was planning to assemble everything myself, why do you ask?

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'66 Dodge Dart

If that's the "factory number" you are quoting then there is more to it than that, over bore doesn't get you much on a slant six (more clearance if using bigger valves), but porting does... A lot depends on makign the package work, bigger cam = higher operating range (i.e. best power at 3000 rpm), more cam requires more compression, now that the VE is bumped, it will want to breathe better, valves, porting, bigger carb, better exhaust to support.

I approached the 225 hp mark at the crank with this formula which is like using a bigger club to whack something:

12:1 SCR (Will barely run on 92 super, prefers 110 leaded race gas, about a 1/4" cut between the head and deck)
O/S valves, lots of porting (prepare to spend about 8-12 hours and a few dies cutting out all the obstructions including the bottom of the valve guide boss intruding into the port.
FatPak intake with Holley 600 cfm carb (mpg is same as driving a 360 equipped truck)
Over bore .060
Headers (these are a must to get the most out of the exhaust event for power)
Heavily modified short slot distributor/no vacuum advance during races.
OCG 549 250/250 @ 50 .549 lift 111 LSA to shorten overlap event to help hyperpak combat reversion in the runners, degreed at 103.
Comes to about a 9.2:1 DCR
Idle is about 14-15" Hg on the vacc gauge, a bit lower in higher gears.
Will throw a 3200 lb car into low 15's, would probably throw an early-A into the 14's which is about where most yesteryear performance builds run.
The Holley 2280 and BBD are setup for a certain band of engine configuration (stock engine with emissions requirements, up to a 9:1 build with RV cam), once you go outside that "comfort zone" it may not work right....it will starve the engine of CFM which in turn can cause other issues (limit the rpm you can operate, not meter gas correctly, etc...).
There is a fair amount of modification I had to do to get the Holley 390 to work right on a street hyperpak with even a mild build, so bear in mind you will have a lot of shake down time getting it all to run right.
It cuts down on build $$$, and allows you to inspect the parts and measure before they go together, you will need to be sure to have some engine building experience to look at clearances if you go with the long rod build, and make sure that the oiling holes are in the correct locations, etc...It goes easier at the machine shop if you come in with what they need to do after you've sized everything up, and you will get less argument from them if they aren't as cooperative.

The 195bhp figure comes from the hyperpak article on allpar.com.

I think the confusion is from my lack of expressing that I'm looking at advertised gross hp numbers, not net hp. So I want to make power somewhat equivalent to a stock (or very mild) SB V8 from the mid-late '60s. This would be around 250hp gross or something like 170-190hp net. So I think that puts us back on track, right?

I really appreciate all the advice and builds, good stuff. I know I'll be asking a lot more questions once I have some measurements to share.

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'66 Dodge Dart

Just keep in mind that in layman's terms that horsepower is a function of torque and typically describes the engines ability to do work, but on the race track/in the performance realm HP describes the engines top end or what it's limit is....torque is the real motivator, and describes the ability to move the vehicle depending on weight and how the gear ratios are set up, in drag racing this determines your launch....on the street the torque curve will be a major determining factor in mpg (the reasons to keep your cruise speeds in the peak or power band of the cam, and why RV cams have a nice fat flat torque band with all around good mpg...)

I would say for what you are aiming at doing the erson 10:1 build will get what you want at 190 hp with a moderate wide torque band...