I have an 88 305 TPI (MAF). I'm looking to upgrade for more power but want to keep my TPI. I just thing it's the coolest looking thing ever!! Anyway, I plan on using the following items:

Trick Flow 490 HP Super 23 Top-End Engine Kits for Small Block Chevrolet
Summit Racing TFS-K314-490-440
http://store.summitracing.com/partde...0&autoview=sku
Cam specs are: 246/254 degree duration at .050, .495/.510 in. lift, with 1.5 ratio rockers and a 112 degree lobe separation.

GM Performance Parts 350 C.I.D. Short Block Engines
Summit Racing NAL-12556121
http://store.summitracing.com/partde...1&autoview=sku

I'll will burn a custom PROM. So my questions are:
Will my TPI bolt on to these heads? (There is a note that reads, "Will not fit centerbolt-style intake manifolds.")
What HP can I expect?
With 18cc dished pistons and 72cc combustion chambers, what will be my compression?

Any input is welcome. Thank you.

 

You going to put stock TPI on top of that setup?

that combo will be a missmatch. That cam is way to big for that motor and most motors. That cam duration wise will be very hard to tune and want to push lots of rpms, where TPI doesnt want to go. TPI cant support it


that shortblock with 18cc dished pistons will have a very low compression ratio...too low for aluminum heads i feel. Especially with 72cc chambers. It will be around 8.3 to 1... great for boost, but not good for performance naturally aspirated. you will want high 9's atleast. I'd actually want to see 10.5 to 1 which will require flat top pistons and 64 cc chambers. You'll run just fine on pump gas with 10.0-10.5 compression

I got 11 to 1 on my 383 and i'm driving great on 93 octane but i think it will run on 91

 

Considder a head with a smaller chamber and use thin gaskets but I would stay under 9.7 to 1.

 

Thanks for the quick replies guys. I thought the cam might be too aggressive even with my TPI with all the home porting that can be done. There is another combo on that same line with 62cc heads and this cam profile:
228/234 degree duration at .050, .480/.494 in. lift, with 1.5 ratio rockers and a 110° lobe separation
TFS-K314-420-395
http://store.summitracing.com/partde...5&autoview=sku

Will the compression be about 9.5? What HP can I expect?
Thanks again.

 

That cam is alittle bit better for ported TPI. still a bit large but you can get it to work ok.

definately keep compression up with aluminum heads else the car will feel like a dog on the low end with a cam that large. the 110 lsa helps but low compression doesnt

Iron heads keep it under 10. aluminum keep it under 11 i'd say for a street pump gas car.

I'm not sure if your shortblock you have in mind in that link is zero decked or not, that will be important to know when sizing gaskets. if you do keep quench height to the proper .040" +- .005" range, then your compression with those heads will be 9.1 to 1. not bad, but not optimal by any means. I'd go a step smaller cam in that case or have the heads milled. easier to choose a smaller cam, something like 224/230 on a 112 or 218/224 on a 110 i'd say.

shave the heads to 58cc will be 9.5 to 1. thats where you'd like to start out at.

Do they sell another shortblock with less dish in the pistons? try finding something in the 5-12cc dished range to bump up that compression

As far as hp, its hard to say but maybe get to near 300-330whp depending on tune/exhaust/compression etc. Biggest thing is how much porting do you have done to that manifold?

Heads wont fit centerbolt style intakes which means 87-up angled middle bolt style intakes wont bolt onto those heads. you need to A) get a corvette manifold or B) drill out your holes to straight up so it will align properly. that be the easiest thing to do

 

Thank you. That's exactly the info I was looking for. For the intake, I believe TPIS or Edelbrock make a Vortec style heads intake manifold for TPI, would that work? I'm not sure if I can get that short block with flat pistons but I'll look into it. I'll try to get that Trick Flow kit with a milder cam. Is there any other heads/cam combo that are sold as a kit that you could recommend. Thanks again.

 

vortec intake is for vortec style heads and will not work with trickflow heads. now you could do a vortec head combination that will run as good as trickflow for abit less money and work better with that compression. But iron is heavier

Most aftermarket TPI intakes tho i believe are drilled for both intake bolt setups but i'm not 100% sure

as far as other kits, i dont know of anything else. you dont really need a kit tho, just need to select the heads with the proper springs you need and then order a cam kit. not all that hard. Just gotta match cam to the springs

 

I have the same opinion about Vortec heads. They flow great but are heavier. The only reason I was going with the kit is because it has all the parts I'd need and everything is matched like I'd have to do if I bought separately. Just trying to save a little work and a little money. However, if I buy separately, I'll probably go with AFR heads. I've read great things about them but I'm not sure if they flow that much better that Trick Flow heads (or if the difference is worth the extra dough). In any case, I'm not even sure that I'll get use out of the better flow since my top priority is keeping the TPI intake. Thanks yet again. You've been very helpful.

 

With a TPI you are not going to see any of the top end flow benefits the AFR's have over the Trickflows so save your money.

Still think you should look for cam with lots more lift and less duration.
like
TPiS Z409 : 226 / .520 w 1.5
Lingenfelter 211 : 211 / 219 .530 / .560
or cheaper Comp versions with similar specs.
All proven TPI cams
People have run TPI successfully on 383's but most upgrade to aftermarket base and big tubes

 

I'm partial to AFR's. I got them on my 383 and its a very driveable car that runs 11's. I think the AFR heads are the best you can get just about for 23 degree small block heads

TPI or not, i do think they are beneficial

 

Thanks for the input vetteoz. However, I'm sticking to a 350 because upgrading my TPI with aftermarket parts, which I know would be needed for a 383, would blow my budget. This is where my knowledge lacks. I've never been able to really understand cam specs. (I've read a few articles and always wind up forgetting everything bec. of lack of practice) Anyway, what is the difference between having more lift and less duration and viceversa. I understand that lift is the distance between the seat and the valve and that duration is how long the valve is open. However, does one move my power band one way or the other? Or rev quicker to get into the power band sooner? Also, I've always been under the impression that higher lift cams wear out quicker as well as the valves. Any comments?