for a set of heads. I'm wanting to know the proper (scientific) way of going about this. what are the things that you would measure and why. what do I need to be aware of and the more technical the better. formulas welcome and prefered. I'm looking for a well balanced thought out weekend warior.

I am wanting the engine wizards to go at this. but I want to know why they made a choice and how they made it. I'm wanting to become better at matching up parts and components.

limits.
around a $2000 limit to spend for the short block $3000 total heads are paid for already
pump gas compatable
N2O is the only power adder that I'll consider.
for an 3spd auto car 3000lbs no higher than a 3500 stall (foot brake)
3.73-4.56 rear gears

I already have a set of ported ford 302 E7TE heads this is what I know about them off hand I can find any other info you may need.

Intake runner volume 145cc
chamber volume 58cc
min cross sectional area 1.7
1.94 & 1.6 valves manly pro flow
flow intake....ex
.200 120........95
.300 170........120
.400 204........160
.500 243........180
.550 254........184


pic of the intake runner-raised around .100 side walls widened a bit and extinsive bow and short side work.

flow sheet


have at it guys

 

This is pretty hard to understand....

You have XXX heads and you want to know what to do with them? Not really starting off with a blank sheet of paper.....

There are some good formulas by Larry Meaux around here for what you are looking to do....

Basically with your small runner and cross section of 1.7 I wouldn't put them on anything bigger than a 302 if you want to get the thing over 6000rpm. I would say if the port is a good port and you use a race style intake high 400's is possible with that head. I would run some gear and the max stall you are looking at and try to shift it in the 6500-7000range.

Bret

 

If I ran them on a 351 and brought the shift points down would that slow me down? looking for the reason you prefer the 302.

 

You are asking what cam to use and what static CR? Or what? If you are aksing for a treatise on cam design, you are asking a lot. A search will net some valuable information, but I think you have an unrealistic expectation if you think someone is going to write up a textbook for you. Even though it is interesting, you are lucky in that you aren't talking about any kind of an odd combo and therefore don't NEED to delve too deep into theory to find a good combo. There is a lot of knowledge already out there about what works on a SBF. Maybe not as much as for SBC's, but still plenty.

I also can't understand how/why you have already picked the gear andf converter you are going to run. That is backwards. You need to know what rpm the motor is going to run before deciding on gear/tire size and converter stall.

Also: what kind of cam are you planning to run? HR, SR, flat tappet??

Rich

 

A 351 will bring the RPM max down in to stock 5.0L range, I mean really a low RPM pig. From what I have seen in the past ford guys never put enough head on a 351 motor and this would be very true here.

RPM is your friend if you want to go fast.

Rich also has some very good points too.

Bret

 

I was thinking about a hyd flat tappet cam. and I chose the gear and stall speeds in advance because I think that anymore than that is too much of a comprimise on streetabilty. I was looking for cam rpm rang and ci recomendations and why you would choose them. if it isn't worth your time to reply then don't some people just like to help and voice thier opinions that is all I'm looking for. thanks to the two of you for your reply's and I understand what you are saying. I'm just looking for more insite and different opinions on a proper combination for these limits.

 

also I was told by another profecional engine builder that for a street engine it is smarter to go with more cubes. that you can run just as fast but need less gear and rpms to do it. is this not true? he told me that a set of cylinder heads can only make so much hp regardless of the combo and that the ci doesn't make any difference exceppt that the rpm that the engine has to turn to reach it is less with more ci.

 

Yes, more cubes is almost always good on a street motor. I'd suggest something on the order of 225/235-230/240 on a 110LSA with ~.550" lift. Ought to take a 351 to ~6,000rpm and have great mid-range, what you want for a street car. Based on experience though, not theory, sorry.

Rich

 

If it's a street motor that's a weekend warrior I would do either a 347 289/5.0L based motor or a 351W.

I'm partical to solid flat tappet cams over hyd flat tappets. The flat tappet limits you enough, might as well set the lash every once in a while.

With around 350 cubes and those heads the motor is going to be dead at 6000rpm and starting to nose over at 5200rpm. Your going to need some cam so I would look at a single pattern (same intake and exhaust durations) in the 236-245 range @ .050. A set of 1 5/8 headers, a Performer RPM Air Gap or a Vic Jr intake and a Demon 650(Vic Jr) or 750 (Performer RPM). This should get you over 400hp SAE.

If you need any specific parts just shoot me a e-mail and we can see what we can do.

Bret

 

Hey Bret: why the single pattern? His exhaust flow is ~75% of intake, so don't you want to compensate for that? I can see that the duration I picked may be a little short for a 351 though.

Rich

 

The total E/I with a single pattern cam works out to around 75-76%. Between the flow and the valve sizes (the large exhaust valve relative to the small intake) it would make more midrange TQ and not hurt HP at all with a single pattern cam. Now if it was a SBC with a 2.08/1.6 valve setup (and the added intake flow to match) it would probably like a split pattern with more exhaust.

Bret

 

Get a set of TFS heads or the Edelbrock heads fully ported with 2.050/1.60.Get a Anderson Motorsports cam and lifters.Build a 356 351 Windsor,stock crank,truck rods and Probe pistons, 12-1 compression with a Victor Jr fixed to correct fuel distribution with a 750 double pumper and go run 10.80's on motor with a c-4 and good converter with stock rear with C-clip eliminators 31 spline and a pro Auburn 4.10 gear. 28x9"Hoosier's and a 1.46 60 ft@3200lbs.And a bunch of chassis tweaks.

Been there done that.But mine had a Crower flat tappet solid.'86 'stang

 

thing is, unless you are doing something really cutting edge- like competative- you are DEFINATELY best off going "cook book" and basically copying a combo.

if you ARE going cutting edge, ask many question, and listen closely. dont worry if you miss something though, they wont tell you what it is you are looking for.

R&D IS ULTRA expensive nowadays. That dude that won engine builders competition last year- big ford guy, cant think of his name. his policy is to have all his dynos ALWAYS running. he has built a reputation for WEARING OUT dynos! He had some GREAT stuff in his last engine. He spends a LOT in R&D though. a lot. and the big things he finds, he isn't going to post on the internet.

If some NASCAR team comes out with a motor making 25-50more hp and clearly dominates a track like dayton with power and some reporter asks "so what was your secret" they sure as hell aren't going to say "well we found that if we (insert what they did) we were able to make 30 more hp and increase BSFC by 4%!"

their answer would be "well hedrick just got us a great running car all around, xxxxx did a great job drivnig and the crew really did a great job supporting us"