Trying to put together a decent combo here. I've got plenty of time to plan it out before I start spending the money. I actually want to copy Mike Crew's combo somewhat. Read that old thread several times. I want some more opinions here. Track/dyno proven combos would help. I want to see if I am on the right track and am up for any suggestions. I am looking to stay tpi for now. Racing is something I might do once a year. I just want a fun street engine with a buttload of torque that can keep up with modern muscle somewhat.

I have a Edelbrock base and Slp Runners ( bought these off Mike Crews wayyyyy back when he first took them off his car) So Vortecs are out of question unless I want to get another base. Everyone raves about a certain brand of head. I am leaning towards Darts because of their rep and a lot of people i know off the boards swear by them. They have aluminum version that looks good.

I assume I need to stay near 200 runner volume or under to maintain streetability without outflowing the TPI? I am probably going with under 70cc combustion chamber size to get good compression with whatever engine/pistons I use. I'll figure that out as I go. Which head have you guys had the most luck with? I've heard AFRs need extensive cleaning up out of the box. What flows the best as is?

I am looking at starting with a 355 or 383 shortblock. I am probably buying one outright instead of building. They are some really good assemblies out there by different venders.


For cam, I am leaning towards the CC xtreme 8-503-8
.503/.510
224/230 @ .050
112 LSA

I see a ton of recommendations for this one on here.
This will probably need retrofit lifters depending on the block I use.

All this is going into a 89 Iroc 700r4 (having this built) with at least 2600-2800 stall converter and 3:42 gears. Other things I already have but don't need to list to stay on topic. Opinions and suggestions are very welcome. In the meantime I'll keep searching. lol

 

You need to decide what cubes you're going to run and the compression ratio you'll be comfortable with before picking the heads and cam. As far as heads go, it's more about what they flow and the flow ratio (flow/volume and exhaust/intake) than it is about name brand. Heads over 200cc may not necessarily be too large either,,, it will depend on how how much flow increases with the larger volumea and the cubes. I generally determine how much flow is needed for the combination to produce the desired power or ET then look for the smallest volume runner that will flow the numbers. What ever it ends up being,,, is what it is. If you buy a head strictly on volume,,, you run a high risk of not being happy with the ETs or dyno numbers.

 

AFR all the way dont waste money on anything else. unless its 100 % cnc ported and it out flows the afr. Afr is a great buy.

 

The engines I am looking at state with 64cc heads 10.40 on the 383 and 9.40 on the 355. I mentioned that one cam because like I said, I see several people with anything from a 355 to 406 using them with good results. I don't have a ton of time for trial and error is why I am asking.

If I was to set a ET/dyno goal for the motor (which I am not) I think high to mid 12s and maybe a little over 300 rwhp would be my goal with perfect conditions. I am not wanting to put up a unrealistic goal since I'll still be ltr.

I think a 383 would put me there easier but it would simply be out of air unless I really extrude hone those runners and base out. Like I said I probably won't race it hardly at all and won't be needing a high winding motor. The torque will most likely make me happy. I just want a great performing street car.

 

You can generate the ET and power goals you indicated with a set of heads flowing 245cfm at cam lift with duration in the neighborhood of 220 degrees at .050 with the 355, 2800 stall and 3.42 gears - assuming a good flowing 3" exhaust system. How much of the power you can get to the ground will determine whether you run high or mid 12s. Going with the 383, a set of 195 AFR heads, and a cam in the 225 - 230 range on a 112 spread, you'll be a good bit quicker assuming traction,, which will be critical to make the lower ETs. It'll make more HP and TQ at a lower RPM than the 355,, and you'll still have to shift it a few hundred RPM sooner even with the larger cam and better heads,, but why would you care as long as it's faster and more powerfull? Plus if you ever go with a different (shorter runner) intake later on, the larger cubes will let the car still work well with the 2800 stall. Long story short, go with the cubes regardless of the intake you want to run.

 

From what I know AFRs are one of the best heads you can buy out of the box.

I'm currently running a set and have had great luck with them.

 

AFR's all the way. I just bought a set. Should be on the road in 3 weeks. Definate difference in sound. They have dyno charts on their website. Great numbers with low rpm range. Perfect for TPI intakes. Check their website Air Flow Research

 

which heads are better for the l98 180 or 195 afr heads and what is the stock combustion chamber size?

 

Things are changing in head design. For a high performance 355 I would look for something in the 200cc range. AFR and Dart are supposed to have newer designed aluminum heads out this year if not already in certain runner sizes. Call them for advice. Regarding head volume decide which motor you want to build before ordering the heads. If a 355 you will most likely want 64cc heads. The cam you chose will decide your final compression ratio. The larger the cam the higher you will want the compression.

For a 383 I would go with something a little larger maybe in the 210 to 215cc range. Regarding cams remember that lift is your friend. You are cheating yourself with the low lift cam you mentioned and with the heads you are talking about. You want the cam to open quickly, stay open for a longer period for the duration and close quickly. In other words "dwell" time.

I would look into something like the Comp Cams XE or XFI line or a custom cam. Infact a custom cam would be the way to go. You can get it taylored for your set up.

With your Edelbrock TPI manifold you need to get it opened up. Guys in or club here are getting them Extrude Honed. The Accel version flowed around 276cfm when Extrude Honed. With opened up SLP runners and plenum you can make plenty of horsepower.

 

Great info everyone. Thanks!

The edelbrock base has been opened up quite a bit. The guy I bought it from had it on a super ram 420 that he switched out to put a miniram on. The ports are huge compared to a stock tpi base. I am not sure how much he took out but he did a good job. I assume he had them extrude honed because there are no uneven porting marks. He also had metal welded onto the outer ports to cover the ports on his huge Brodix heads he was running. I had to cut that off just to use them because it hit my valve covers.

The Slps, are basically stock minus some porting done by myself. The plenum is hogged out pretty good.

As for cam, I'll keep researching. I see comp cams is the one company that seems to keep the EFI crowd happy. Keep in mind I have always been a flat tappet guy. These huge roller lift numbers are intimidating at first. lol

 

If that's the case, then the ports could be opened up to a 1207 intake gasket. I'd check to see if they're at a 1207 or 1206 opening, Regardless, your head selection just increased dramatically. I recommended the 195s on the 383 based on the typical 1205 sized opening on the intake. Now,,, I totally agree with 1989GTA, go bigger to take advantage of the flow increase they typically provide,,, like the 210 AFR (same price as the 195s). With the 210s or similar heads as "89" stated, go for the lift a hydraulic roller can give you,, which could easily convert into 40 horses over a flat tappet hydraulic on these type heads (ones that flow a lot at .600 lift). Plus the extra lift really wont effect your street manners - it will cost more (just have to deside if the money difference is worth the 40 horses,, which doesn't come cheap once you hit this level). Regardless of what heads you go with you're going to HAVE to at least port match them to the intake,,, especially if it's opened to a 1207. If you stick that on a set of heads opened to a 1205 gasket,, it'll flat KILL the head flow due to the turbulance it will cause at the head port.

 

He used it to cover the ports and he used a 1206 gasket. After I shimmed that metal off (since I didn't need it) it fit to a 1205 gasket perfectly.

 

It was more like extra metal just to seal the port up on the heads he had. Whoever did it, didn't do a great job. I just shimmed that off.

 

you think we like AFR

 

it depend on your rpm range also. for a stock motor setup the 180s will be fine. 68cc and 74cc are your choices for the AFR
the 195 are good for higher rpms. as long as you stay with the stock cubic in.