I plan to run a 306 with flattop pistons a little over .500 lift flat tappet cam. I have decided on the bottom end and want some advice on heads. I had thought of going with gt40's but with a little more money I can get aftermarket heads. This is the set of heads I was planning on getting. I am wanting your opinion on them. They are the trick flow 170 twisted wedge. Here is the link http://www.summitracing.com/parts/TFS-51400002/ In your opinion what is the best heads for a street strip sbf
Before you decide on heads, you first need to verify the piston's deck clearance. Not all 302 flat tops yeild the same compression ratio. The pin heights vary from 1.585 to 1.619. That's a half point in compression ratio. You don't want the 1.585's combined with 64 cc chambers. Unless you're planning on a blower or turbo.
For a street strip application, I would go with the Trick Flow Specialties High Port Street/Strip heads, 257cfm @ .500 out of the box set up for solid roller. $1,287.95 purchased and setup through Total Engine Airflow to insure quality.
X3 on the AFR 165s... i had them on my 302...306 and now on my 347... ...when you say...flattops...are you talking...no eyebrows (like the '86 5.0)? ...LMAFRs...:Handshake
You cant beat any AFR for out of the box performance, We have flow benched 3 sets, 165s, 185s, 205s. They pretty much flow what they say out of the box. We have flowed others that was supposed to beat the AFRs but couldn't. We bolted on the 4 set back in the summer, The quality was second to none as all sets have been. Just be sure you order them with the rite spring pressures as usually they come with solid lift springs, Then you have to spend an additional 100+ bucks for the rite springs.
With a half inch lift on your cam, what will the duration be (at .050")? The 185s from AFR are the best on the market for the 302 up to 6500 rpm. Now if you were going to rev it real high or stroke it to higher CU" then you might want to use the 185s. AFR has the highest numbers flat out (dyno HP #s not flow numbers). The amount of air a head will flow is only half (or less) of the story. The HP it produces is a better determination of its value on an engine.
If a head has low flow numbers i can promise you it wont make as much H.P., Given that, mid flow numbers are more important than high flow numbers. ( a valve spends more time at mid lift than at full lift, Because it sees it twice). But i wouldn't say that the flow is half or less of the story. If you have a velocity probe you can learn a lot from flowing heads. Head flow numbers and H.P. go hand in hand if the information is used correctly. But yes if you don't understand flow numbers or how to interpret the information then yes the flow numbers wouldn't mean much. But there is much literature out there on the subject, its your choice whether to use it or not.
I think I am going to go with the edelbrock e street heads. Edelbrock did a build using 9 to 1 compression performer cam e street heads performer rpm intake 750 eddy carb and headers. It made 321hp which is what I want. Afr's would be nice but I can't see paying $1400 for a set of heads for a street strip car. I am figuring the build they did would put my car in the high 7's or low 8's pretty easy in the 1/8 mile and mid 12's in the 1/4
Just a comparison but AFR did a build on a stock bottom end roller motor and made 400 with the 165's, but i can see saving the dough especially if they will do what you want. Nothing wrong with Edelbrock stuff.
If you're only going for that power level then you may want to check these out www.thumperoforangepark.com
